NEWS
author wenzelm
Thu Mar 27 15:32:15 2008 +0100 (2008-03-27)
changeset 26435 bdce320cd426
parent 26434 d004b791218e
child 26445 17223cf843d8
permissions -rw-r--r--
eliminated delayed theory setup
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Syntax: symbol \<chi> is now considered a letter.  Potential
    10 INCOMPATIBILITY in identifier syntax etc.
    11 
    12 * Outer syntax: string tokens may contain arbitrary character codes
    13 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
    14 "foo_bar".
    15 
    16 * Outer syntax: string tokens no longer admit escaped white space,
    17 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
    18 white space directly.
    19 
    20 * Theory loader: use_thy (and similar operations) no longer set the
    21 implicit ML context, which was occasionally hard to predict and in
    22 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
    23 provides a proper context already.
    24 
    25 * Theory loader: old-style ML proof scripts being *attached* to a thy
    26 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
    27 'use' within a theory file will do the job.
    28 
    29 
    30 *** Pure ***
    31 
    32 * Eliminated theory ProtoPure.  Potential INCOMPATIBILITY.
    33 
    34 * Command 'setup': discontinued implicit version.
    35 
    36 * Instantiation target allows for simultaneous specification of class
    37 instance operations together with an instantiation proof.
    38 Type-checking phase allows to refer to class operations uniformly.
    39 See HOL/Complex/Complex.thy for an Isar example and
    40 HOL/Library/Eval.thy for an ML example.
    41 
    42 * Indexing of literal facts: be more serious about including only
    43 facts from the visible specification/proof context, but not the
    44 background context (locale etc.).  Affects `prop` notation and method
    45 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
    46 situations.
    47 
    48 
    49 *** HOL ***
    50 
    51 * HOL (and FOL): renamed variables in rules imp_elim and swap.
    52 Potential INCOMPATIBILITY.
    53 
    54 * Theory Product_Type: duplicated lemmas split_Pair_apply and injective_fst_snd
    55 removed, use split_eta and prod_eqI instead.  Renamed upd_fst to apfst and upd_snd
    56 to apsnd.  INCOMPATIBILITY.
    57 
    58 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
    59 the same name in theory Orderings:
    60 
    61   less_trans
    62   less_linear
    63   le_imp_less_or_eq
    64   le_less_trans
    65   less_le_trans
    66   less_not_sym
    67   less_asym
    68 
    69 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
    70 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
    71 and different variable names.
    72 
    73 * Library/Option_ord.thy: Canonical order on option type.
    74 
    75 * Library/RBT.thy: New theory of red-black trees, an efficient
    76 implementation of finite maps.
    77 
    78 * Library/Countable.thy: Type class for countable types.
    79 
    80 * Theory Int: The representation of numerals has changed.  The infix
    81 operator BIT and the bit datatype with constructors B0 and B1 have
    82 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
    83 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
    84 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
    85 accordingly.
    86 
    87 * Theory Nat: definition of <= and < on natural numbers no longer
    88 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
    89 le_def and less_def have disappeared.  Consider lemmas not_less
    90 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
    91 
    92 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
    93 (whose purpose mainly is for various fold_set functionals) have been
    94 abandoned in favour of the existing algebraic classes
    95 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
    96 lower_semilattice (resp. upper_semilattice) and linorder.
    97 INCOMPATIBILITY.
    98 
    99 * Theory Transitive_Closure: induct and cases rules now declare proper
   100 case_names ("base" and "step").  INCOMPATIBILITY.
   101 
   102 * Theorem Inductive.lfp_ordinal_induct generalized to complete
   103 lattices.  The form set-specific version is available as
   104 Inductive.lfp_ordinal_induct_set.
   105 
   106 * Theorems "power.simps" renamed to "power_int.simps".
   107 
   108 * Class semiring_div provides basic abstract properties of semirings
   109 with division and modulo operations.  Subsumes former class dvd_mod.
   110 
   111 * Merged theories IntDef, Numeral and IntArith into unified theory
   112 Int.  INCOMPATIBILITY.
   113 
   114 * Theory Library/Code_Index: type "index" now represents natural
   115 numbers rather than integers.  INCOMPATIBILITY.
   116 
   117 * New class "uminus" with operation "uminus" (split of from class
   118 "minus" which now only has operation "minus", binary).
   119 INCOMPATIBILITY.
   120 
   121 * New primrec package.  Specification syntax conforms in style to
   122 definition/function/....  No separate induction rule is provided.  The
   123 "primrec" command distinguishes old-style and new-style specifications
   124 by syntax.  The former primrec package is now named OldPrimrecPackage.
   125 When adjusting theories, beware: constants stemming from new-style
   126 primrec specifications have authentic syntax.
   127 
   128 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   129 
   130 * Library/ListVector: new theory of arithmetic vector operations.
   131 
   132 * Constants "card", "internal_split", "option_map" now with authentic
   133 syntax.  INCOMPATIBILITY.
   134 
   135 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   136 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   137 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   138 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   139 Sup_set_def, le_def, less_def, option_map_def now with object
   140 equality.  INCOMPATIBILITY.
   141 
   142 * Method "induction_scheme" derives user-specified induction rules
   143 from wellfounded induction and completeness of patterns. This factors
   144 out some operations that are done internally by the function package
   145 and makes them available separately. See "HOL/ex/Induction_Scheme.thy"
   146 for examples,
   147 
   148 * Records. Removed K_record, and replaced it by pure lambda term
   149 %x. c. The simplifier setup is now more robust against eta expansion.
   150 INCOMPATIBILITY: in cases explicitly referring to K_record.
   151 
   152 * Metis prover is now an order of magnitude faster, and also works
   153 with multithreading.
   154 
   155 * Sledgehammer no longer produces structured proofs by default. To enable, 
   156 declare [[sledgehammer_full = true]]. Attributes reconstruction_modulus,  
   157 reconstruction_sorts renamed sledgehammer_modulus, sledgehammer_sorts. 
   158 INCOMPATIBILITY.
   159 
   160 *** ZF ***
   161 
   162 * Renamed theories:
   163 
   164   Datatype.thy  -> Datatype_ZF.thy
   165   Inductive.thy -> Inductive_ZF.thy
   166   Int.thy       -> Int_ZF.thy
   167   IntDiv.thy    -> IntDiv_ZF.thy
   168   Nat.thy       -> Nat_ZF.thy
   169   List.thy      -> List_ZF.thy
   170   Main.thy      -> Main_ZF.thy
   171 
   172  This is to allow to load both ZF and HOL in the same session.
   173 
   174  INCOMPATIBILITY: ZF theories that import individual theories below
   175  Main might need to be adapted. For compatibility, a new 
   176  "theory Main imports Main_ZF begin end" is provided, so if you just
   177  imported "Main", no changes are needed.
   178 
   179 
   180 *** ML ***
   181 
   182 * Functor NamedThmsFun: data is available to the user as dynamic fact
   183 (of the same name).
   184 
   185 * Removed obsolete "use_legacy_bindings" function.  INCOMPATIBILITY.
   186 
   187 * ML within Isar: antiquotation @{const name} or @{const
   188 name(typargs)} produces statically-checked Const term.
   189 
   190 * The ``print mode'' is now a thread-local value derived from a global
   191 template (the former print_mode reference), thus access becomes
   192 non-critical.  The global print_mode reference is for session
   193 management only; user-code should use print_mode_value,
   194 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   195 
   196 * system/system_out provides a robust way to invoke external shell
   197 commands, with propagation of interrupts (after Poly/ML 5.2).  Do not
   198 use OS.Process.system etc. directly.
   199 
   200 
   201 *** System ***
   202 
   203 * System: removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the
   204 documented way of changing the user's settings is via
   205 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   206 script.
   207 
   208 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   209 in accordance with Proof General 3.7, which prefers GNU emacs.
   210 
   211 * Multithreading.max_threads := 0 refers to the number of actual CPU
   212 cores of the underlying machine, which is a good starting point for
   213 optimal performance tuning.  The corresponding usedir option -M allows
   214 "max" as an alias for "0".  WARNING: does not work on certain versions
   215 of Mac OS (with Poly/ML 5.1).
   216 
   217 * isatool tty runs Isabelle process with plain tty interaction;
   218 optional line editor may be specified via ISABELLE_LINE_EDITOR
   219 setting, the default settings attempt to locate "ledit" and "rlwrap".
   220 
   221 * isatool browser now works with Cygwin as well, using general
   222 "javapath" function defined in Isabelle process environment.
   223 
   224 * isabelle-process: non-ML sessions are run with "nice", to prevent
   225 Isabelle from flooding interactive front-ends (notably ProofGeneral /
   226 XEmacs).
   227 
   228 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   229 provides general wrapper for managing an Isabelle process in a robust
   230 fashion, with ``cooked'' output from stdin/stderr.
   231 
   232 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   233 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   234 
   235 
   236 
   237 New in Isabelle2007 (November 2007)
   238 -----------------------------------
   239 
   240 *** General ***
   241 
   242 * More uniform information about legacy features, notably a
   243 warning/error of "Legacy feature: ...", depending on the state of the
   244 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   245 legacy features will disappear eventually.
   246 
   247 * Theory syntax: the header format ``theory A = B + C:'' has been
   248 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   249 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   250 
   251 * Theory syntax: the old non-Isar theory file format has been
   252 discontinued altogether.  Note that ML proof scripts may still be used
   253 with Isar theories; migration is usually quite simple with the ML
   254 function use_legacy_bindings.  INCOMPATIBILITY.
   255 
   256 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   257 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   258 quotes.
   259 
   260 * Theory loader: be more serious about observing the static theory
   261 header specifications (including optional directories), but not the
   262 accidental file locations of previously successful loads.  The strict
   263 update policy of former update_thy is now already performed by
   264 use_thy, so the former has been removed; use_thys updates several
   265 theories simultaneously, just as 'imports' within a theory header
   266 specification, but without merging the results.  Potential
   267 INCOMPATIBILITY: may need to refine theory headers and commands
   268 ROOT.ML which depend on load order.
   269 
   270 * Theory loader: optional support for content-based file
   271 identification, instead of the traditional scheme of full physical
   272 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   273 (cf. the system manual).  The new scheme allows to work with
   274 non-finished theories in persistent session images, such that source
   275 files may be moved later on without requiring reloads.
   276 
   277 * Theory loader: old-style ML proof scripts being *attached* to a thy
   278 file (with the same base name as the theory) are considered a legacy
   279 feature, which will disappear eventually. Even now, the theory loader
   280 no longer maintains dependencies on such files.
   281 
   282 * Syntax: the scope for resolving ambiguities via type-inference is
   283 now limited to individual terms, instead of whole simultaneous
   284 specifications as before. This greatly reduces the complexity of the
   285 syntax module and improves flexibility by separating parsing and
   286 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   287 'fixes' etc.) are required in rare situations.
   288 
   289 * Syntax: constants introduced by new-style packages ('definition',
   290 'abbreviation' etc.) are passed through the syntax module in
   291 ``authentic mode''. This means that associated mixfix annotations
   292 really stick to such constants, independently of potential name space
   293 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   294 trees are represented slightly differently, may need to adapt syntax
   295 translations accordingly. Use CONST marker in 'translations' and
   296 @{const_syntax} antiquotation in 'parse_translation' etc.
   297 
   298 * Legacy goal package: reduced interface to the bare minimum required
   299 to keep existing proof scripts running.  Most other user-level
   300 functions are now part of the OldGoals structure, which is *not* open
   301 by default (consider isatool expandshort before open OldGoals).
   302 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   303 these tend to cause confusion about the actual goal (!) context being
   304 used here, which is not necessarily the same as the_context().
   305 
   306 * Command 'find_theorems': supports "*" wild-card in "name:"
   307 criterion; "with_dups" option.  Certain ProofGeneral versions might
   308 support a specific search form (see ProofGeneral/CHANGES).
   309 
   310 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   311 by default, which means that "prems" (and also "fixed variables") are
   312 suppressed from proof state output.  Note that the ProofGeneral
   313 settings mechanism allows to change and save options persistently, but
   314 older versions of Isabelle will fail to start up if a negative prems
   315 limit is imposed.
   316 
   317 * Local theory targets may be specified by non-nested blocks of
   318 ``context/locale/class ... begin'' followed by ``end''.  The body may
   319 contain definitions, theorems etc., including any derived mechanism
   320 that has been implemented on top of these primitives.  This concept
   321 generalizes the existing ``theorem (in ...)'' towards more versatility
   322 and scalability.
   323 
   324 * Proof General interface: proper undo of final 'end' command;
   325 discontinued Isabelle/classic mode (ML proof scripts).
   326 
   327 
   328 *** Document preparation ***
   329 
   330 * Added antiquotation @{theory name} which prints the given name,
   331 after checking that it refers to a valid ancestor theory in the
   332 current context.
   333 
   334 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   335 check the given source text as ML type/structure, printing verbatim.
   336 
   337 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   338 "c args == rhs" given in the current context.  (Any number of
   339 arguments may be given on the LHS.)
   340 
   341 
   342 *** Pure ***
   343 
   344 * The 'class' package offers a combination of axclass and locale to
   345 achieve Haskell-like type classes in Isabelle.  Definitions and
   346 theorems within a class context produce both relative results (with
   347 implicit parameters according to the locale context), and polymorphic
   348 constants with qualified polymorphism (according to the class
   349 context).  Within the body context of a 'class' target, a separate
   350 syntax layer ("user space type system") takes care of converting
   351 between global polymorphic consts and internal locale representation.
   352 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   353 "isatool doc classes" provides a tutorial.
   354 
   355 * Generic code generator framework allows to generate executable
   356 code for ML and Haskell (including Isabelle classes).  A short usage
   357 sketch:
   358 
   359     internal compilation:
   360         export_code <list of constants (term syntax)> in SML
   361     writing SML code to a file:
   362         export_code <list of constants (term syntax)> in SML <filename>
   363     writing OCaml code to a file:
   364         export_code <list of constants (term syntax)> in OCaml <filename>
   365     writing Haskell code to a bunch of files:
   366         export_code <list of constants (term syntax)> in Haskell <filename>
   367 
   368     evaluating closed propositions to True/False using code generation:
   369         method ``eval''
   370 
   371 Reasonable default setup of framework in HOL.
   372 
   373 Theorem attributs for selecting and transforming function equations theorems:
   374 
   375     [code fun]:        select a theorem as function equation for a specific constant
   376     [code fun del]:    deselect a theorem as function equation for a specific constant
   377     [code inline]:     select an equation theorem for unfolding (inlining) in place
   378     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   379 
   380 User-defined serializations (target in {SML, OCaml, Haskell}):
   381 
   382     code_const <and-list of constants (term syntax)>
   383       {(target) <and-list of const target syntax>}+
   384 
   385     code_type <and-list of type constructors>
   386       {(target) <and-list of type target syntax>}+
   387 
   388     code_instance <and-list of instances>
   389       {(target)}+
   390         where instance ::= <type constructor> :: <class>
   391 
   392     code_class <and_list of classes>
   393       {(target) <and-list of class target syntax>}+
   394         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   395 
   396 code_instance and code_class only are effective to target Haskell.
   397 
   398 For example usage see src/HOL/ex/Codegenerator.thy and
   399 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   400 generation from Isabelle/HOL theories is available via "isatool doc
   401 codegen".
   402 
   403 * Code generator: consts in 'consts_code' Isar commands are now
   404 referred to by usual term syntax (including optional type
   405 annotations).
   406 
   407 * Command 'no_translations' removes translation rules from theory
   408 syntax.
   409 
   410 * Overloaded definitions are now actually checked for acyclic
   411 dependencies.  The overloading scheme is slightly more general than
   412 that of Haskell98, although Isabelle does not demand an exact
   413 correspondence to type class and instance declarations.
   414 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   415 exotic versions of overloading -- at the discretion of the user!
   416 
   417 Polymorphic constants are represented via type arguments, i.e. the
   418 instantiation that matches an instance against the most general
   419 declaration given in the signature.  For example, with the declaration
   420 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   421 as c(nat).  Overloading is essentially simultaneous structural
   422 recursion over such type arguments.  Incomplete specification patterns
   423 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   424 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   425 Command 'print_theory' outputs the normalized system of recursive
   426 equations, see section "definitions".
   427 
   428 * Configuration options are maintained within the theory or proof
   429 context (with name and type bool/int/string), providing a very simple
   430 interface to a poor-man's version of general context data.  Tools may
   431 declare options in ML (e.g. using Attrib.config_int) and then refer to
   432 these values using Config.get etc.  Users may change options via an
   433 associated attribute of the same name.  This form of context
   434 declaration works particularly well with commands 'declare' or
   435 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   436 very easy to avoid global references, which would not observe Isar
   437 toplevel undo/redo and fail to work with multithreading.
   438 
   439 Various global ML references of Pure and HOL have been turned into
   440 configuration options:
   441 
   442   Unify.search_bound		unify_search_bound
   443   Unify.trace_bound		unify_trace_bound
   444   Unify.trace_simp		unify_trace_simp
   445   Unify.trace_types		unify_trace_types
   446   Simplifier.simp_depth_limit	simp_depth_limit
   447   Blast.depth_limit		blast_depth_limit
   448   DatatypeProp.dtK		datatype_distinctness_limit
   449   fast_arith_neq_limit  	fast_arith_neq_limit
   450   fast_arith_split_limit	fast_arith_split_limit
   451 
   452 * Named collections of theorems may be easily installed as context
   453 data using the functor NamedThmsFun (see also
   454 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   455 attributes; there is also a toplevel print command.  This facility is
   456 just a common case of general context data, which is the preferred way
   457 for anything more complex than just a list of facts in canonical
   458 order.
   459 
   460 * Isar: command 'declaration' augments a local theory by generic
   461 declaration functions written in ML.  This enables arbitrary content
   462 being added to the context, depending on a morphism that tells the
   463 difference of the original declaration context wrt. the application
   464 context encountered later on.
   465 
   466 * Isar: proper interfaces for simplification procedures.  Command
   467 'simproc_setup' declares named simprocs (with match patterns, and body
   468 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   469 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   470 
   471 * Isar: an extra pair of brackets around attribute declarations
   472 abbreviates a theorem reference involving an internal dummy fact,
   473 which will be ignored later --- only the effect of the attribute on
   474 the background context will persist.  This form of in-place
   475 declarations is particularly useful with commands like 'declare' and
   476 'using', for example ``have A using [[simproc a]] by simp''.
   477 
   478 * Isar: method "assumption" (and implicit closing of subproofs) now
   479 takes simple non-atomic goal assumptions into account: after applying
   480 an assumption as a rule the resulting subgoals are solved by atomic
   481 assumption steps.  This is particularly useful to finish 'obtain'
   482 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   483 without referring to the original premise "!!x. P x ==> thesis" in the
   484 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   485 more permissive.
   486 
   487 * Isar: implicit use of prems from the Isar proof context is
   488 considered a legacy feature.  Common applications like ``have A .''
   489 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   490 referencing facts explicitly here improves readability and
   491 maintainability of proof texts.
   492 
   493 * Isar: improper proof element 'guess' is like 'obtain', but derives
   494 the obtained context from the course of reasoning!  For example:
   495 
   496   assume "EX x y. A x & B y"   -- "any previous fact"
   497   then guess x and y by clarify
   498 
   499 This technique is potentially adventurous, depending on the facts and
   500 proof tools being involved here.
   501 
   502 * Isar: known facts from the proof context may be specified as literal
   503 propositions, using ASCII back-quote syntax.  This works wherever
   504 named facts used to be allowed so far, in proof commands, proof
   505 methods, attributes etc.  Literal facts are retrieved from the context
   506 according to unification of type and term parameters.  For example,
   507 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   508 theorems in the current context, then these are valid literal facts:
   509 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   510 
   511 There is also a proof method "fact" which does the same composition
   512 for explicit goal states, e.g. the following proof texts coincide with
   513 certain special cases of literal facts:
   514 
   515   have "A" by fact                 ==  note `A`
   516   have "A ==> B" by fact           ==  note `A ==> B`
   517   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   518   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   519 
   520 * Isar: ":" (colon) is no longer a symbolic identifier character in
   521 outer syntax.  Thus symbolic identifiers may be used without
   522 additional white space in declarations like this: ``assume *: A''.
   523 
   524 * Isar: 'print_facts' prints all local facts of the current context,
   525 both named and unnamed ones.
   526 
   527 * Isar: 'def' now admits simultaneous definitions, e.g.:
   528 
   529   def x == "t" and y == "u"
   530 
   531 * Isar: added command 'unfolding', which is structurally similar to
   532 'using', but affects both the goal state and facts by unfolding given
   533 rewrite rules.  Thus many occurrences of the 'unfold' method or
   534 'unfolded' attribute may be replaced by first-class proof text.
   535 
   536 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   537 and command 'unfolding' now all support object-level equalities
   538 (potentially conditional).  The underlying notion of rewrite rule is
   539 analogous to the 'rule_format' attribute, but *not* that of the
   540 Simplifier (which is usually more generous).
   541 
   542 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   543 premises of a theorem by n. Useful in conjunction with drule.
   544 
   545 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   546 method expression within a sandbox consisting of the first N
   547 sub-goals, which need to exist.  For example, ``simp_all [3]''
   548 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   549 simplifies all new goals that emerge from applying rule foo to the
   550 originally first one.
   551 
   552 * Isar: schematic goals are no longer restricted to higher-order
   553 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   554 expected.
   555 
   556 * Isar: the conclusion of a long theorem statement is now either
   557 'shows' (a simultaneous conjunction, as before), or 'obtains'
   558 (essentially a disjunction of cases with local parameters and
   559 assumptions).  The latter allows to express general elimination rules
   560 adequately; in this notation common elimination rules look like this:
   561 
   562   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   563     assumes "EX x. P x"
   564     obtains x where "P x"
   565 
   566   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   567     assumes "A & B"
   568     obtains A and B
   569 
   570   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   571     assumes "A | B"
   572     obtains
   573       A
   574     | B
   575 
   576 The subsequent classical rules even refer to the formal "thesis"
   577 explicitly:
   578 
   579   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   580     obtains "~ thesis"
   581 
   582   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   583     obtains "thesis ==> something"
   584 
   585 The actual proof of an 'obtains' statement is analogous to that of the
   586 Isar proof element 'obtain', only that there may be several cases.
   587 Optional case names may be specified in parentheses; these will be
   588 available both in the present proof and as annotations in the
   589 resulting rule, for later use with the 'cases' method (cf. attribute
   590 case_names).
   591 
   592 * Isar: the assumptions of a long theorem statement are available as
   593 "assms" fact in the proof context.  This is more appropriate than the
   594 (historical) "prems", which refers to all assumptions of the current
   595 context, including those from the target locale, proof body etc.
   596 
   597 * Isar: 'print_statement' prints theorems from the current theory or
   598 proof context in long statement form, according to the syntax of a
   599 top-level lemma.
   600 
   601 * Isar: 'obtain' takes an optional case name for the local context
   602 introduction rule (default "that").
   603 
   604 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   605 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   606 to occur.
   607 
   608 * Pure: syntax "CONST name" produces a fully internalized constant
   609 according to the current context.  This is particularly useful for
   610 syntax translations that should refer to internal constant
   611 representations independently of name spaces.
   612 
   613 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   614 instead of "FOO ". This allows multiple binder declarations to coexist
   615 in the same context.  INCOMPATIBILITY.
   616 
   617 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   618 primitive that also works in a locale context (both for constants and
   619 fixed variables). Type declaration and internal syntactic representation
   620 of given constants retrieved from the context. Likewise, the
   621 'no_notation' command allows to remove given syntax annotations from the
   622 current context.
   623 
   624 * Isar/locales: new derived specification elements 'axiomatization',
   625 'definition', 'abbreviation', which support type-inference, admit
   626 object-level specifications (equality, equivalence).  See also the
   627 isar-ref manual.  Examples:
   628 
   629   axiomatization
   630     eq  (infix "===" 50) where
   631     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   632 
   633   definition "f x y = x + y + 1"
   634   definition g where "g x = f x x"
   635 
   636   abbreviation
   637     neq  (infix "=!=" 50) where
   638     "x =!= y == ~ (x === y)"
   639 
   640 These specifications may be also used in a locale context.  Then the
   641 constants being introduced depend on certain fixed parameters, and the
   642 constant name is qualified by the locale base name.  An internal
   643 abbreviation takes care for convenient input and output, making the
   644 parameters implicit and using the original short name.  See also
   645 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   646 entities from a monomorphic theory.
   647 
   648 Presently, abbreviations are only available 'in' a target locale, but
   649 not inherited by general import expressions.  Also note that
   650 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   651 'translations' in common applications.  The "no_abbrevs" print mode
   652 prevents folding of abbreviations in term output.
   653 
   654 Concrete syntax is attached to specified constants in internal form,
   655 independently of name spaces.  The parse tree representation is
   656 slightly different -- use 'notation' instead of raw 'syntax', and
   657 'translations' with explicit "CONST" markup to accommodate this.
   658 
   659 * Pure/Isar: unified syntax for new-style specification mechanisms
   660 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
   661 full type inference and dummy patterns ("_").  For example:
   662 
   663   definition "K x _ = x"
   664 
   665   inductive conj for A B
   666   where "A ==> B ==> conj A B"
   667 
   668 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   669 the current context.  Print mode "no_abbrevs" prevents inversion of
   670 abbreviations on output.
   671 
   672 * Isar/locales: improved parameter handling: use of locales "var" and
   673 "struct" no longer necessary; - parameter renamings are no longer
   674 required to be injective.  For example, this allows to define
   675 endomorphisms as locale endom = homom mult mult h.
   676 
   677 * Isar/locales: changed the way locales with predicates are defined.
   678 Instead of accumulating the specification, the imported expression is
   679 now an interpretation.  INCOMPATIBILITY: different normal form of
   680 locale expressions.  In particular, in interpretations of locales with
   681 predicates, goals repesenting already interpreted fragments are not
   682 removed automatically.  Use methods `intro_locales' and
   683 `unfold_locales'; see below.
   684 
   685 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   686 provide backward reasoning on locales predicates.  The methods are
   687 aware of interpretations and discharge corresponding goals.
   688 `intro_locales' is less aggressive then `unfold_locales' and does not
   689 unfold predicates to assumptions.
   690 
   691 * Isar/locales: the order in which locale fragments are accumulated
   692 has changed.  This enables to override declarations from fragments due
   693 to interpretations -- for example, unwanted simp rules.
   694 
   695 * Isar/locales: interpretation in theories and proof contexts has been
   696 extended.  One may now specify (and prove) equations, which are
   697 unfolded in interpreted theorems.  This is useful for replacing
   698 defined concepts (constants depending on locale parameters) by
   699 concepts already existing in the target context.  Example:
   700 
   701   interpretation partial_order ["op <= :: [int, int] => bool"]
   702     where "partial_order.less (op <=) (x::int) y = (x < y)"
   703 
   704 Typically, the constant `partial_order.less' is created by a
   705 definition specification element in the context of locale
   706 partial_order.
   707 
   708 * Method "induct": improved internal context management to support
   709 local fixes and defines on-the-fly. Thus explicit meta-level
   710 connectives !!  and ==> are rarely required anymore in inductive goals
   711 (using object-logic connectives for this purpose has been long
   712 obsolete anyway). Common proof patterns are explained in
   713 src/HOL/Induct/Common_Patterns.thy, see also
   714 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
   715 examples.
   716 
   717 * Method "induct": improved handling of simultaneous goals. Instead of
   718 introducing object-level conjunction, the statement is now split into
   719 several conclusions, while the corresponding symbolic cases are nested
   720 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
   721 see src/HOL/Induct/Common_Patterns.thy, for example.
   722 
   723 * Method "induct": mutual induction rules are now specified as a list
   724 of rule sharing the same induction cases. HOL packages usually provide
   725 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
   726 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
   727 mutual induction rules differently, i.e. like this:
   728 
   729   (induct rule: foo_bar.inducts)
   730   (induct set: foo bar)
   731   (induct pred: foo bar)
   732   (induct type: foo bar)
   733 
   734 The ML function ProjectRule.projections turns old-style rules into the
   735 new format.
   736 
   737 * Method "coinduct": dual of induction, see
   738 src/HOL/Library/Coinductive_List.thy for various examples.
   739 
   740 * Method "cases", "induct", "coinduct": the ``(open)'' option is
   741 considered a legacy feature.
   742 
   743 * Attribute "symmetric" produces result with standardized schematic
   744 variables (index 0).  Potential INCOMPATIBILITY.
   745 
   746 * Simplifier: by default the simplifier trace only shows top level
   747 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   748 default. Thus there is less danger of being flooded by the trace. The
   749 trace indicates where parts have been suppressed.
   750   
   751 * Provers/classical: removed obsolete classical version of elim_format
   752 attribute; classical elim/dest rules are now treated uniformly when
   753 manipulating the claset.
   754 
   755 * Provers/classical: stricter checks to ensure that supplied intro,
   756 dest and elim rules are well-formed; dest and elim rules must have at
   757 least one premise.
   758 
   759 * Provers/classical: attributes dest/elim/intro take an optional
   760 weight argument for the rule (just as the Pure versions).  Weights are
   761 ignored by automated tools, but determine the search order of single
   762 rule steps.
   763 
   764 * Syntax: input syntax now supports dummy variable binding "%_. b",
   765 where the body does not mention the bound variable.  Note that dummy
   766 patterns implicitly depend on their context of bounds, which makes
   767 "{_. _}" match any set comprehension as expected.  Potential
   768 INCOMPATIBILITY -- parse translations need to cope with syntactic
   769 constant "_idtdummy" in the binding position.
   770 
   771 * Syntax: removed obsolete syntactic constant "_K" and its associated
   772 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   773 for example "A -> B" => "Pi A (%_. B)".
   774 
   775 * Pure: 'class_deps' command visualizes the subclass relation, using
   776 the graph browser tool.
   777 
   778 * Pure: 'print_theory' now suppresses certain internal declarations by
   779 default; use '!' option for full details.
   780 
   781 
   782 *** HOL ***
   783 
   784 * Method "metis" proves goals by applying the Metis general-purpose
   785 resolution prover (see also http://gilith.com/software/metis/).
   786 Examples are in the directory MetisExamples.  WARNING: the
   787 Isabelle/HOL-Metis integration does not yet work properly with
   788 multi-threading.
   789   
   790 * Command 'sledgehammer' invokes external automatic theorem provers as
   791 background processes.  It generates calls to the "metis" method if
   792 successful. These can be pasted into the proof.  Users do not have to
   793 wait for the automatic provers to return.  WARNING: does not really
   794 work with multi-threading.
   795 
   796 * New "auto_quickcheck" feature tests outermost goal statements for
   797 potential counter-examples.  Controlled by ML references
   798 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
   799 5000 milliseconds).  Fails silently if statements is outside of
   800 executable fragment, or any other codgenerator problem occurs.
   801 
   802 * New constant "undefined" with axiom "undefined x = undefined".
   803 
   804 * Added class "HOL.eq", allowing for code generation with polymorphic
   805 equality.
   806 
   807 * Some renaming of class constants due to canonical name prefixing in
   808 the new 'class' package:
   809 
   810     HOL.abs ~> HOL.abs_class.abs
   811     HOL.divide ~> HOL.divide_class.divide
   812     0 ~> HOL.zero_class.zero
   813     1 ~> HOL.one_class.one
   814     op + ~> HOL.plus_class.plus
   815     op - ~> HOL.minus_class.minus
   816     uminus ~> HOL.minus_class.uminus
   817     op * ~> HOL.times_class.times
   818     op < ~> HOL.ord_class.less
   819     op <= > HOL.ord_class.less_eq
   820     Nat.power ~> Power.power_class.power
   821     Nat.size ~> Nat.size_class.size
   822     Numeral.number_of ~> Numeral.number_class.number_of
   823     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
   824     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
   825     Orderings.min ~> Orderings.ord_class.min
   826     Orderings.max ~> Orderings.ord_class.max
   827     Divides.op div ~> Divides.div_class.div
   828     Divides.op mod ~> Divides.div_class.mod
   829     Divides.op dvd ~> Divides.div_class.dvd
   830 
   831 INCOMPATIBILITY.  Adaptions may be required in the following cases:
   832 
   833 a) User-defined constants using any of the names "plus", "minus",
   834 "times", "less" or "less_eq". The standard syntax translations for
   835 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
   836 names.
   837 
   838 b) Variables named "plus", "minus", "times", "less", "less_eq"
   839 INCOMPATIBILITY: use more specific names.
   840 
   841 c) Permutative equations (e.g. "a + b = b + a")
   842 Since the change of names also changes the order of terms, permutative
   843 rewrite rules may get applied in a different order. Experience shows
   844 that this is rarely the case (only two adaptions in the whole Isabelle
   845 distribution).  INCOMPATIBILITY: rewrite proofs
   846 
   847 d) ML code directly refering to constant names
   848 This in general only affects hand-written proof tactics, simprocs and
   849 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
   850 Consider using @{const_name} antiquotation.
   851 
   852 * New class "default" with associated constant "default".
   853 
   854 * Function "sgn" is now overloaded and available on int, real, complex
   855 (and other numeric types), using class "sgn".  Two possible defs of
   856 sgn are given as equational assumptions in the classes sgn_if and
   857 sgn_div_norm; ordered_idom now also inherits from sgn_if.
   858 INCOMPATIBILITY.
   859 
   860 * Locale "partial_order" now unified with class "order" (cf. theory
   861 Orderings), added parameter "less".  INCOMPATIBILITY.
   862 
   863 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
   864 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
   865 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
   866 
   867 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
   868 changed order of proof goals in instance proofs.
   869 
   870 * The transitivity reasoner for partial and linear orders is set up
   871 for classes "order" and "linorder".  Instances of the reasoner are available
   872 in all contexts importing or interpreting the corresponding locales.
   873 Method "order" invokes the reasoner separately; the reasoner
   874 is also integrated with the Simplifier as a solver.  Diagnostic
   875 command 'print_orders' shows the available instances of the reasoner
   876 in the current context.
   877 
   878 * Localized monotonicity predicate in theory "Orderings"; integrated
   879 lemmas max_of_mono and min_of_mono with this predicate.
   880 INCOMPATIBILITY.
   881 
   882 * Formulation of theorem "dense" changed slightly due to integration
   883 with new class dense_linear_order.
   884 
   885 * Uniform lattice theory development in HOL.
   886 
   887     constants "meet" and "join" now named "inf" and "sup"
   888     constant "Meet" now named "Inf"
   889 
   890     classes "meet_semilorder" and "join_semilorder" now named
   891       "lower_semilattice" and "upper_semilattice"
   892     class "lorder" now named "lattice"
   893     class "comp_lat" now named "complete_lattice"
   894 
   895     Instantiation of lattice classes allows explicit definitions
   896     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   897 
   898   INCOMPATIBILITY.  Theorem renames:
   899 
   900     meet_left_le            ~> inf_le1
   901     meet_right_le           ~> inf_le2
   902     join_left_le            ~> sup_ge1
   903     join_right_le           ~> sup_ge2
   904     meet_join_le            ~> inf_sup_ord
   905     le_meetI                ~> le_infI
   906     join_leI                ~> le_supI
   907     le_meet                 ~> le_inf_iff
   908     le_join                 ~> ge_sup_conv
   909     meet_idempotent         ~> inf_idem
   910     join_idempotent         ~> sup_idem
   911     meet_comm               ~> inf_commute
   912     join_comm               ~> sup_commute
   913     meet_leI1               ~> le_infI1
   914     meet_leI2               ~> le_infI2
   915     le_joinI1               ~> le_supI1
   916     le_joinI2               ~> le_supI2
   917     meet_assoc              ~> inf_assoc
   918     join_assoc              ~> sup_assoc
   919     meet_left_comm          ~> inf_left_commute
   920     meet_left_idempotent    ~> inf_left_idem
   921     join_left_comm          ~> sup_left_commute
   922     join_left_idempotent    ~> sup_left_idem
   923     meet_aci                ~> inf_aci
   924     join_aci                ~> sup_aci
   925     le_def_meet             ~> le_iff_inf
   926     le_def_join             ~> le_iff_sup
   927     join_absorp2            ~> sup_absorb2
   928     join_absorp1            ~> sup_absorb1
   929     meet_absorp1            ~> inf_absorb1
   930     meet_absorp2            ~> inf_absorb2
   931     meet_join_absorp        ~> inf_sup_absorb
   932     join_meet_absorp        ~> sup_inf_absorb
   933     distrib_join_le         ~> distrib_sup_le
   934     distrib_meet_le         ~> distrib_inf_le
   935 
   936     add_meet_distrib_left   ~> add_inf_distrib_left
   937     add_join_distrib_left   ~> add_sup_distrib_left
   938     is_join_neg_meet        ~> is_join_neg_inf
   939     is_meet_neg_join        ~> is_meet_neg_sup
   940     add_meet_distrib_right  ~> add_inf_distrib_right
   941     add_join_distrib_right  ~> add_sup_distrib_right
   942     add_meet_join_distribs  ~> add_sup_inf_distribs
   943     join_eq_neg_meet        ~> sup_eq_neg_inf
   944     meet_eq_neg_join        ~> inf_eq_neg_sup
   945     add_eq_meet_join        ~> add_eq_inf_sup
   946     meet_0_imp_0            ~> inf_0_imp_0
   947     join_0_imp_0            ~> sup_0_imp_0
   948     meet_0_eq_0             ~> inf_0_eq_0
   949     join_0_eq_0             ~> sup_0_eq_0
   950     neg_meet_eq_join        ~> neg_inf_eq_sup
   951     neg_join_eq_meet        ~> neg_sup_eq_inf
   952     join_eq_if              ~> sup_eq_if
   953 
   954     mono_meet               ~> mono_inf
   955     mono_join               ~> mono_sup
   956     meet_bool_eq            ~> inf_bool_eq
   957     join_bool_eq            ~> sup_bool_eq
   958     meet_fun_eq             ~> inf_fun_eq
   959     join_fun_eq             ~> sup_fun_eq
   960     meet_set_eq             ~> inf_set_eq
   961     join_set_eq             ~> sup_set_eq
   962     meet1_iff               ~> inf1_iff
   963     meet2_iff               ~> inf2_iff
   964     meet1I                  ~> inf1I
   965     meet2I                  ~> inf2I
   966     meet1D1                 ~> inf1D1
   967     meet2D1                 ~> inf2D1
   968     meet1D2                 ~> inf1D2
   969     meet2D2                 ~> inf2D2
   970     meet1E                  ~> inf1E
   971     meet2E                  ~> inf2E
   972     join1_iff               ~> sup1_iff
   973     join2_iff               ~> sup2_iff
   974     join1I1                 ~> sup1I1
   975     join2I1                 ~> sup2I1
   976     join1I1                 ~> sup1I1
   977     join2I2                 ~> sup1I2
   978     join1CI                 ~> sup1CI
   979     join2CI                 ~> sup2CI
   980     join1E                  ~> sup1E
   981     join2E                  ~> sup2E
   982 
   983     is_meet_Meet            ~> is_meet_Inf
   984     Meet_bool_def           ~> Inf_bool_def
   985     Meet_fun_def            ~> Inf_fun_def
   986     Meet_greatest           ~> Inf_greatest
   987     Meet_lower              ~> Inf_lower
   988     Meet_set_def            ~> Inf_set_def
   989 
   990     Sup_def                 ~> Sup_Inf
   991     Sup_bool_eq             ~> Sup_bool_def
   992     Sup_fun_eq              ~> Sup_fun_def
   993     Sup_set_eq              ~> Sup_set_def
   994 
   995     listsp_meetI            ~> listsp_infI
   996     listsp_meet_eq          ~> listsp_inf_eq
   997 
   998     meet_min                ~> inf_min
   999     join_max                ~> sup_max
  1000 
  1001 * Added syntactic class "size"; overloaded constant "size" now has
  1002 type "'a::size ==> bool"
  1003 
  1004 * Internal reorganisation of `size' of datatypes: size theorems
  1005 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1006 simplification rules by default!); theorems "prod.size" now named
  1007 "*.size".
  1008 
  1009 * Class "div" now inherits from class "times" rather than "type".
  1010 INCOMPATIBILITY.
  1011 
  1012 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1013 Linorder etc.  have disappeared; operations defined in terms of
  1014 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1015 
  1016 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1017 
  1018 * HOL-Word: New extensive library and type for generic, fixed size
  1019 machine words, with arithemtic, bit-wise, shifting and rotating
  1020 operations, reflection into int, nat, and bool lists, automation for
  1021 linear arithmetic (by automatic reflection into nat or int), including
  1022 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1023 arithmetic type classes, supporting automatic simplification of
  1024 numerals on all operations.
  1025 
  1026 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1027 
  1028 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1029 
  1030 * Code generator library theories:
  1031   - Code_Integer represents HOL integers by big integer literals in target
  1032     languages.
  1033   - Code_Char represents HOL characters by character literals in target
  1034     languages.
  1035   - Code_Char_chr like Code_Char, but also offers treatment of character
  1036     codes; includes Code_Integer.
  1037   - Executable_Set allows to generate code for finite sets using lists.
  1038   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1039     denominator).
  1040   - Executable_Real implements a subset of real numbers, namly those
  1041     representable by rational numbers.
  1042   - Efficient_Nat implements natural numbers by integers, which in general will
  1043     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1044     includes Code_Integer.
  1045   - Code_Index provides an additional datatype index which is mapped to
  1046     target-language built-in integers.
  1047   - Code_Message provides an additional datatype message_string which is isomorphic to
  1048     strings; messages are mapped to target-language strings.
  1049 
  1050 * New package for inductive predicates
  1051 
  1052   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1053 
  1054     inductive
  1055       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1056       for z_1 :: U_1 and ... and z_n :: U_m
  1057     where
  1058       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1059     | ...
  1060 
  1061   with full support for type-inference, rather than
  1062 
  1063     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1064 
  1065     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1066     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1067 
  1068     inductive "s z_1 ... z_m"
  1069     intros
  1070       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1071       ...
  1072 
  1073   For backward compatibility, there is a wrapper allowing inductive
  1074   sets to be defined with the new package via
  1075 
  1076     inductive_set
  1077       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1078       for z_1 :: U_1 and ... and z_n :: U_m
  1079     where
  1080       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1081     | ...
  1082 
  1083   or
  1084 
  1085     inductive_set
  1086       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1087       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1088       for z_1 :: U_1 and ... and z_n :: U_m
  1089     where
  1090       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1091     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1092     | ...
  1093 
  1094   if the additional syntax "p ..." is required.
  1095 
  1096   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1097   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1098 
  1099   INCOMPATIBILITIES:
  1100 
  1101   - Since declaration and definition of inductive sets or predicates
  1102     is no longer separated, abbreviations involving the newly
  1103     introduced sets or predicates must be specified together with the
  1104     introduction rules after the 'where' keyword (see above), rather
  1105     than before the actual inductive definition.
  1106 
  1107   - The variables in induction and elimination rules are now
  1108     quantified in the order of their occurrence in the introduction
  1109     rules, rather than in alphabetical order. Since this may break
  1110     some proofs, these proofs either have to be repaired, e.g. by
  1111     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1112     statements of the form
  1113 
  1114       case (rule_i a_i_1 ... a_i_{k_i})
  1115 
  1116     or the old order of quantification has to be restored by explicitly adding
  1117     meta-level quantifiers in the introduction rules, i.e.
  1118 
  1119       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1120 
  1121   - The format of the elimination rules is now
  1122 
  1123       p z_1 ... z_m x_1 ... x_n ==>
  1124         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1125         ==> ... ==> P
  1126 
  1127     for predicates and
  1128 
  1129       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1130         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1131         ==> ... ==> P
  1132 
  1133     for sets rather than
  1134 
  1135       x : s z_1 ... z_m ==>
  1136         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1137         ==> ... ==> P
  1138 
  1139     This may require terms in goals to be expanded to n-tuples
  1140     (e.g. using case_tac or simplification with the split_paired_all
  1141     rule) before the above elimination rule is applicable.
  1142 
  1143   - The elimination or case analysis rules for (mutually) inductive
  1144     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1145     list of rules "p_1_..._p_k.elims" is no longer available.
  1146 
  1147 * New package "function"/"fun" for general recursive functions,
  1148 supporting mutual and nested recursion, definitions in local contexts,
  1149 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1150 for small examples, and the separate tutorial on the function
  1151 package. The old recdef "package" is still available as before, but
  1152 users are encouraged to use the new package.
  1153 
  1154 * Method "lexicographic_order" automatically synthesizes termination
  1155 relations as lexicographic combinations of size measures. 
  1156 
  1157 * Case-expressions allow arbitrary constructor-patterns (including
  1158 "_") and take their order into account, like in functional
  1159 programming.  Internally, this is translated into nested
  1160 case-expressions; missing cases are added and mapped to the predefined
  1161 constant "undefined". In complicated cases printing may no longer show
  1162 the original input but the internal form. Lambda-abstractions allow
  1163 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1164 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1165 variable.
  1166 
  1167 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1168 is an abbreviation for "of_nat :: nat => int". The simplification
  1169 rules for "of_nat" have been changed to work like "int" did
  1170 previously.  Potential INCOMPATIBILITY:
  1171   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1172   - of_nat_diff and of_nat_mult are no longer default simp rules
  1173 
  1174 * Method "algebra" solves polynomial equations over (semi)rings using
  1175 Groebner bases. The (semi)ring structure is defined by locales and the
  1176 tool setup depends on that generic context. Installing the method for
  1177 a specific type involves instantiating the locale and possibly adding
  1178 declarations for computation on the coefficients.  The method is
  1179 already instantiated for natural numbers and for the axiomatic class
  1180 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1181 CALCULEMUS 2007 for the general principles underlying this
  1182 architecture of context-aware proof-tools.
  1183 
  1184 * Method "ferrack" implements quantifier elimination over
  1185 special-purpose dense linear orders using locales (analogous to
  1186 "algebra"). The method is already installed for class
  1187 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1188 rat, etc.
  1189 
  1190 * Former constant "List.op @" now named "List.append".  Use ML
  1191 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1192 circumvent possible incompatibilities when working on ML level.
  1193 
  1194 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1195 
  1196 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1197 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1198 
  1199 * New syntax for Haskell-like list comprehension (input only), eg.
  1200 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1201 
  1202 * The special syntax for function "filter" has changed from [x :
  1203 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1204 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1205 
  1206 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1207 defined on nat only, as an abbreviation for [a..<Suc b]
  1208 INCOMPATIBILITY.
  1209 
  1210 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1211 
  1212 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1213 
  1214 * New lemma collection field_simps (an extension of ring_simps) for
  1215 manipulating (in)equations involving division. Multiplies with all
  1216 denominators that can be proved to be non-zero (in equations) or
  1217 positive/negative (in inequations).
  1218 
  1219 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1220 have been improved and renamed to ring_simps, group_simps and
  1221 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1222 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1223 
  1224 * Theory Library/Commutative_Ring: switched from recdef to function
  1225 package; constants add, mul, pow now curried.  Infix syntax for
  1226 algebraic operations.
  1227 
  1228 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1229 INCOMPATIBILITY.
  1230 
  1231 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1232 INCOMPATIBILITY.
  1233 
  1234 * HOL/records: generalised field-update to take a function on the
  1235 field rather than the new value: r(|A := x|) is translated to A_update
  1236 (K x) r The K-combinator that is internally used is called K_record.
  1237 INCOMPATIBILITY: Usage of the plain update functions has to be
  1238 adapted.
  1239  
  1240 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1241 * x = 0, which are required for a semiring.  Richer structures do not
  1242 inherit from semiring_0 anymore, because this property is a theorem
  1243 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1244 there is more to prove, but this is mostly trivial.
  1245 
  1246 * Class "recpower" is generalized to arbitrary monoids, not just
  1247 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1248 commutativity or semiring properties additionally.
  1249 
  1250 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1251 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1252 better use 'abbreviation'.
  1253 
  1254 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1255 
  1256 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1257 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1258 significant changes for setting up numeral syntax for types:
  1259   - New constants Numeral.pred and Numeral.succ instead
  1260       of former Numeral.bin_pred and Numeral.bin_succ.
  1261   - Use integer operations instead of bin_add, bin_mult and so on.
  1262   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1263   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1264 
  1265 See src/HOL/Integ/IntArith.thy for an example setup.
  1266 
  1267 * Command 'normal_form' computes the normal form of a term that may
  1268 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1269 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1270 heavy-duty computations because the functions are compiled to ML
  1271 first.  Correspondingly, a method "normalization" is provided.  See
  1272 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1273 
  1274 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1275 25 like -->); output depends on the "iff" print_mode, the default is
  1276 "A = B" (with priority 50).
  1277 
  1278 * Relations less (<) and less_eq (<=) are also available on type bool.
  1279 Modified syntax to disallow nesting without explicit parentheses,
  1280 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1281 INCOMPATIBILITY.
  1282 
  1283 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1284 
  1285 * Relation composition operator "op O" now has precedence 75 and binds
  1286 stronger than union and intersection. INCOMPATIBILITY.
  1287 
  1288 * The old set interval syntax "{m..n(}" (and relatives) has been
  1289 removed.  Use "{m..<n}" (and relatives) instead.
  1290 
  1291 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1292 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1293 ``declare [[simproc del: neq]]''.
  1294 
  1295 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1296 True/False.
  1297 
  1298 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1299 
  1300 * Theorem setsum_mult renamed to setsum_right_distrib.
  1301 
  1302 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1303 ``rule'' method.
  1304 
  1305 * Reimplemented methods "sat" and "satx", with several improvements:
  1306 goals no longer need to be stated as "<prems> ==> False", equivalences
  1307 (i.e. "=" on type bool) are handled, variable names of the form
  1308 "lit_<n>" are no longer reserved, significant speedup.
  1309 
  1310 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1311 zChaff is still supported as well.
  1312 
  1313 * 'inductive' and 'datatype': provide projections of mutual rules,
  1314 bundled as foo_bar.inducts;
  1315 
  1316 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1317 Library.
  1318 
  1319 * Library: moved theory Accessible_Part to main HOL.
  1320 
  1321 * Library: added theory Coinductive_List of potentially infinite lists
  1322 as greatest fixed-point.
  1323 
  1324 * Library: added theory AssocList which implements (finite) maps as
  1325 association lists.
  1326 
  1327 * Method "evaluation" solves goals (i.e. a boolean expression)
  1328 efficiently by compiling it to ML.  The goal is "proved" (via an
  1329 oracle) if it evaluates to True.
  1330 
  1331 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1332 also when invoked by the simplifier.  This results in the Simplifier
  1333 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1334 Configuration option fast_arith_split_limit=0 recovers the old
  1335 behavior.
  1336 
  1337 * Support for hex (0x20) and binary (0b1001) numerals.
  1338 
  1339 * New method: reify eqs (t), where eqs are equations for an
  1340 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1341 parameter, computes a term s::'b and a list xs::'a list and proves the
  1342 theorem I xs s = t. This is also known as reification or quoting. The
  1343 resulting theorem is applied to the subgoal to substitute t with I xs
  1344 s.  If t is omitted, the subgoal itself is reified.
  1345 
  1346 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1347 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1348 where f is supposed to be a computable function (in the sense of code
  1349 generattion). The method uses reify to compute s and xs as above then
  1350 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1351 r and finally gets the theorem t = r, which is again applied to the
  1352 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1353 
  1354 * Reflection: Automatic reification now handels binding, an example is
  1355 available in src/HOL/ex/ReflectionEx.thy
  1356 
  1357 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1358 command 'statespace' that is similar to 'record', but introduces an
  1359 abstract specification based on the locale infrastructure instead of
  1360 HOL types.  This leads to extra flexibility in composing state spaces,
  1361 in particular multiple inheritance and renaming of components.
  1362 
  1363 
  1364 *** HOL-Complex ***
  1365 
  1366 * Hyperreal: Functions root and sqrt are now defined on negative real
  1367 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1368 Nonnegativity side conditions have been removed from many lemmas, so
  1369 that more subgoals may now be solved by simplification; potential
  1370 INCOMPATIBILITY.
  1371 
  1372 * Real: new type classes formalize real normed vector spaces and
  1373 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1374 and norm :: 'a => real.
  1375 
  1376 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1377 reals into other types. The overloaded constant Reals :: 'a set is now
  1378 defined as range of_real; potential INCOMPATIBILITY.
  1379 
  1380 * Real: proper support for ML code generation, including 'quickcheck'.
  1381 Reals are implemented as arbitrary precision rationals.
  1382 
  1383 * Hyperreal: Several constants that previously worked only for the
  1384 reals have been generalized, so they now work over arbitrary vector
  1385 spaces. Type annotations may need to be added in some cases; potential
  1386 INCOMPATIBILITY.
  1387 
  1388   Infinitesimal  :: ('a::real_normed_vector) star set
  1389   HFinite        :: ('a::real_normed_vector) star set
  1390   HInfinite      :: ('a::real_normed_vector) star set
  1391   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1392   monad          :: ('a::real_normed_vector) star => 'a star set
  1393   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1394   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1395   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1396   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1397   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1398   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1399   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1400   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1401   sgn            :: 'a::real_normed_vector => 'a
  1402   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1403 
  1404 * Complex: Some complex-specific constants are now abbreviations for
  1405 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1406 hnorm.  Other constants have been entirely removed in favor of the
  1407 polymorphic versions (INCOMPATIBILITY):
  1408 
  1409   approx        <-- capprox
  1410   HFinite       <-- CFinite
  1411   HInfinite     <-- CInfinite
  1412   Infinitesimal <-- CInfinitesimal
  1413   monad         <-- cmonad
  1414   galaxy        <-- cgalaxy
  1415   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1416   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1417   (ns)deriv     <-- (ns)cderiv
  1418 
  1419 
  1420 *** HOL-Algebra ***
  1421 
  1422 * Formalisation of ideals and the quotient construction over rings.
  1423 
  1424 * Order and lattice theory no longer based on records.
  1425 INCOMPATIBILITY.
  1426 
  1427 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1428 greatest_closed.  INCOMPATIBILITY.
  1429 
  1430 * Method algebra is now set up via an attribute.  For examples see
  1431 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1432 of algebraic structures.
  1433 
  1434 * Renamed theory CRing to Ring.
  1435 
  1436 
  1437 *** HOL-Nominal ***
  1438 
  1439 * Substantial, yet incomplete support for nominal datatypes (binding
  1440 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1441 src/HOL/Nominal/Examples.  Prospective users should consult
  1442 http://isabelle.in.tum.de/nominal/
  1443 
  1444 
  1445 *** ML ***
  1446 
  1447 * ML basics: just one true type int, which coincides with IntInf.int
  1448 (even on SML/NJ).
  1449 
  1450 * ML within Isar: antiquotations allow to embed statically-checked
  1451 formal entities in the source, referring to the context available at
  1452 compile-time.  For example:
  1453 
  1454 ML {* @{sort "{zero,one}"} *}
  1455 ML {* @{typ "'a => 'b"} *}
  1456 ML {* @{term "%x. x"} *}
  1457 ML {* @{prop "x == y"} *}
  1458 ML {* @{ctyp "'a => 'b"} *}
  1459 ML {* @{cterm "%x. x"} *}
  1460 ML {* @{cprop "x == y"} *}
  1461 ML {* @{thm asm_rl} *}
  1462 ML {* @{thms asm_rl} *}
  1463 ML {* @{type_name c} *}
  1464 ML {* @{type_syntax c} *}
  1465 ML {* @{const_name c} *}
  1466 ML {* @{const_syntax c} *}
  1467 ML {* @{context} *}
  1468 ML {* @{theory} *}
  1469 ML {* @{theory Pure} *}
  1470 ML {* @{theory_ref} *}
  1471 ML {* @{theory_ref Pure} *}
  1472 ML {* @{simpset} *}
  1473 ML {* @{claset} *}
  1474 ML {* @{clasimpset} *}
  1475 
  1476 The same works for sources being ``used'' within an Isar context.
  1477 
  1478 * ML in Isar: improved error reporting; extra verbosity with
  1479 ML_Context.trace enabled.
  1480 
  1481 * Pure/General/table.ML: the join operations now works via exceptions
  1482 DUP/SAME instead of type option. This is simpler in simple cases, and
  1483 admits slightly more efficient complex applications.
  1484 
  1485 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1486 use Context.generic instead of just theory.
  1487 
  1488 * Pure: datatype Context.generic joins theory/Proof.context and
  1489 provides some facilities for code that works in either kind of
  1490 context, notably GenericDataFun for uniform theory and proof data.
  1491 
  1492 * Pure: simplified internal attribute type, which is now always
  1493 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1494 local (Proof.context) attributes have been discontinued, while
  1495 minimizing code duplication. Thm.rule_attribute and
  1496 Thm.declaration_attribute build canonical attributes; see also structure
  1497 Context for further operations on Context.generic, notably
  1498 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1499 declarations and definitions.
  1500 
  1501 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1502 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1503 init only required for impure data. INCOMPATIBILITY: empty really need
  1504 to be empty (no dependencies on theory content!)
  1505 
  1506 * Pure/kernel: consts certification ignores sort constraints given in
  1507 signature declarations. (This information is not relevant to the
  1508 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1509 potential INCOMPATIBILITY.
  1510 
  1511 * Pure: axiomatic type classes are now purely definitional, with
  1512 explicit proofs of class axioms and super class relations performed
  1513 internally. See Pure/axclass.ML for the main internal interfaces --
  1514 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1515 AxClass.axiomatize_class/classrel/arity supersede
  1516 Sign.add_classes/classrel/arities.
  1517 
  1518 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1519 global/local versions on theory vs. Proof.context have been
  1520 discontinued; Attrib.syntax and Method.syntax have been adapted
  1521 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1522 attributes, methods, etc.
  1523 
  1524 * Pure: several functions of signature "... -> theory -> theory * ..."
  1525 have been reoriented to "... -> theory -> ... * theory" in order to
  1526 allow natural usage in combination with the ||>, ||>>, |-> and
  1527 fold_map combinators.
  1528 
  1529 * Pure: official theorem names (closed derivations) and additional
  1530 comments (tags) are now strictly separate.  Name hints -- which are
  1531 maintained as tags -- may be attached any time without affecting the
  1532 derivation.
  1533 
  1534 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1535 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1536 achieve the old behaviour.
  1537 
  1538 * Pure: the "Goal" constant is now called "prop", supporting a
  1539 slightly more general idea of ``protecting'' meta-level rule
  1540 statements.
  1541 
  1542 * Pure: Logic.(un)varify only works in a global context, which is now
  1543 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1544 Logic.legacy_(un)varify as temporary workaround.
  1545 
  1546 * Pure: structure Name provides scalable operations for generating
  1547 internal variable names, notably Name.variants etc.  This replaces
  1548 some popular functions from term.ML:
  1549 
  1550   Term.variant		->  Name.variant
  1551   Term.variantlist	->  Name.variant_list
  1552   Term.invent_names	->  Name.invent_list
  1553 
  1554 Note that low-level renaming rarely occurs in new code -- operations
  1555 from structure Variable are used instead (see below).
  1556 
  1557 * Pure: structure Variable provides fundamental operations for proper
  1558 treatment of fixed/schematic variables in a context.  For example,
  1559 Variable.import introduces fixes for schematics of given facts and
  1560 Variable.export reverses the effect (up to renaming) -- this replaces
  1561 various freeze_thaw operations.
  1562 
  1563 * Pure: structure Goal provides simple interfaces for
  1564 init/conclude/finish and tactical prove operations (replacing former
  1565 Tactic.prove).  Goal.prove is the canonical way to prove results
  1566 within a given context; Goal.prove_global is a degraded version for
  1567 theory level goals, including a global Drule.standard.  Note that
  1568 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1569 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1570 in a locale context).
  1571 
  1572 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  1573 and type checking (Syntax.check_term etc.), with common combinations
  1574 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  1575 which are considered legacy and await removal.
  1576 
  1577 * Pure/Syntax: generic interfaces for type unchecking
  1578 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  1579 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  1580 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  1581 available for convenience, but refer to the very same operations using
  1582 a mere theory instead of a full context.
  1583 
  1584 * Isar: simplified treatment of user-level errors, using exception
  1585 ERROR of string uniformly.  Function error now merely raises ERROR,
  1586 without any side effect on output channels.  The Isar toplevel takes
  1587 care of proper display of ERROR exceptions.  ML code may use plain
  1588 handle/can/try; cat_error may be used to concatenate errors like this:
  1589 
  1590   ... handle ERROR msg => cat_error msg "..."
  1591 
  1592 Toplevel ML code (run directly or through the Isar toplevel) may be
  1593 embedded into the Isar toplevel with exception display/debug like
  1594 this:
  1595 
  1596   Isar.toplevel (fn () => ...)
  1597 
  1598 INCOMPATIBILITY, removed special transform_error facilities, removed
  1599 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1600 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1601 -- use plain ERROR instead.
  1602 
  1603 * Isar: theory setup now has type (theory -> theory), instead of a
  1604 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1605 
  1606 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  1607 ProofContext.debug/verbose flags.
  1608 
  1609 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1610 theory before entering a proof state.  Transactions now always see a
  1611 quasi-functional intermediate checkpoint, both in interactive and
  1612 batch mode.
  1613 
  1614 * Isar: simplified interfaces for outer syntax.  Renamed
  1615 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  1616 OuterSyntax.add_parsers -- this functionality is now included in
  1617 OuterSyntax.command etc.  INCOMPATIBILITY.
  1618 
  1619 * Simplifier: the simpset of a running simplification process now
  1620 contains a proof context (cf. Simplifier.the_context), which is the
  1621 very context that the initial simpset has been retrieved from (by
  1622 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1623 (solver, looper etc.) may depend on arbitrary proof data.
  1624 
  1625 * Simplifier.inherit_context inherits the proof context (plus the
  1626 local bounds) of the current simplification process; any simproc
  1627 etc. that calls the Simplifier recursively should do this!  Removed
  1628 former Simplifier.inherit_bounds, which is already included here --
  1629 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1630 specify an explicit context using Simplifier.context/theory_context.
  1631 
  1632 * Simplifier/Classical Reasoner: more abstract interfaces
  1633 change_simpset/claset for modifying the simpset/claset reference of a
  1634 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1635 INCOMPATIBILITY.
  1636 
  1637 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1638 "Trueprop" etc.
  1639 
  1640 
  1641 *** System ***
  1642 
  1643 * settings: the default heap location within ISABELLE_HOME_USER now
  1644 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  1645 Isabelle installations.
  1646 
  1647 * isabelle-process: option -S (secure mode) disables some critical
  1648 operations, notably runtime compilation and evaluation of ML source
  1649 code.
  1650 
  1651 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  1652 
  1653 * Support for parallel execution, using native multicore support of
  1654 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  1655 independent theories, according to the given theory header
  1656 specifications. The maximum number of worker threads is specified via
  1657 usedir option -M or the "max-threads" setting in Proof General. A
  1658 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  1659 to 6 on a 8-core machine.  User-code needs to observe certain
  1660 guidelines for thread-safe programming, see appendix A in the Isar
  1661 Implementation manual.
  1662 
  1663 
  1664 
  1665 New in Isabelle2005 (October 2005)
  1666 ----------------------------------
  1667 
  1668 *** General ***
  1669 
  1670 * Theory headers: the new header syntax for Isar theories is
  1671 
  1672   theory <name>
  1673   imports <theory1> ... <theoryN>
  1674   uses <file1> ... <fileM>
  1675   begin
  1676 
  1677 where the 'uses' part is optional.  The previous syntax
  1678 
  1679   theory <name> = <theory1> + ... + <theoryN>:
  1680 
  1681 will disappear in the next release.  Use isatool fixheaders to convert
  1682 existing theory files.  Note that there is no change in ancient
  1683 non-Isar theories now, but these will disappear soon.
  1684 
  1685 * Theory loader: parent theories can now also be referred to via
  1686 relative and absolute paths.
  1687 
  1688 * Command 'find_theorems' searches for a list of criteria instead of a
  1689 list of constants. Known criteria are: intro, elim, dest, name:string,
  1690 simp:term, and any term. Criteria can be preceded by '-' to select
  1691 theorems that do not match. Intro, elim, dest select theorems that
  1692 match the current goal, name:s selects theorems whose fully qualified
  1693 name contain s, and simp:term selects all simplification rules whose
  1694 lhs match term.  Any other term is interpreted as pattern and selects
  1695 all theorems matching the pattern. Available in ProofGeneral under
  1696 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1697 
  1698   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1699 
  1700 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1701 matching the current goal as introduction rule and not having "HOL."
  1702 in their name (i.e. not being defined in theory HOL).
  1703 
  1704 * Command 'thms_containing' has been discontinued in favour of
  1705 'find_theorems'; INCOMPATIBILITY.
  1706 
  1707 * Communication with Proof General is now 8bit clean, which means that
  1708 Unicode text in UTF-8 encoding may be used within theory texts (both
  1709 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1710 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1711 
  1712   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1713   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1714 
  1715 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1716 Classical Reasoner.  Typical big applications run around 2 times
  1717 faster.
  1718 
  1719 
  1720 *** Document preparation ***
  1721 
  1722 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1723 of raw sources.  Only those symbols that do not require additional
  1724 LaTeX packages (depending on comments in isabellesym.sty) are
  1725 displayed properly, everything else is left verbatim.  isatool display
  1726 and isatool print are used as front ends (these are subject to the
  1727 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1728 
  1729 * Command tags control specific markup of certain regions of text,
  1730 notably folding and hiding.  Predefined tags include "theory" (for
  1731 theory begin and end), "proof" for proof commands, and "ML" for
  1732 commands involving ML code; the additional tags "visible" and
  1733 "invisible" are unused by default.  Users may give explicit tag
  1734 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1735 interpretation of tags is determined by the LaTeX job during document
  1736 preparation: see option -V of isatool usedir, or options -n and -t of
  1737 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1738 \isadroptag.
  1739 
  1740 Several document versions may be produced at the same time via isatool
  1741 usedir (the generated index.html will link all of them).  Typical
  1742 specifications include ''-V document=theory,proof,ML'' to present
  1743 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1744 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1745 these parts without any formal replacement text.  The Isabelle site
  1746 default settings produce ''document'' and ''outline'' versions as
  1747 specified above.
  1748 
  1749 * Several new antiquotations:
  1750 
  1751   @{term_type term} prints a term with its type annotated;
  1752 
  1753   @{typeof term} prints the type of a term;
  1754 
  1755   @{const const} is the same as @{term const}, but checks that the
  1756   argument is a known logical constant;
  1757 
  1758   @{term_style style term} and @{thm_style style thm} print a term or
  1759   theorem applying a "style" to it
  1760 
  1761   @{ML text}
  1762 
  1763 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1764 definitions, equations, inequations etc., 'concl' printing only the
  1765 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1766 to print the specified premise.  TermStyle.add_style provides an ML
  1767 interface for introducing further styles.  See also the "LaTeX Sugar"
  1768 document practical applications.  The ML antiquotation prints
  1769 type-checked ML expressions verbatim.
  1770 
  1771 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1772 and 'text' support optional locale specification '(in loc)', which
  1773 specifies the default context for interpreting antiquotations.  For
  1774 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1775 
  1776 * Option 'locale=NAME' of antiquotations specifies an alternative
  1777 context interpreting the subsequent argument.  For example: @{thm
  1778 [locale=lattice] inf_assoc}.
  1779 
  1780 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1781 a proof context.
  1782 
  1783 * Proper output of antiquotations for theory commands involving a
  1784 proof context (such as 'locale' or 'theorem (in loc) ...').
  1785 
  1786 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1787 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1788 
  1789 * isatool usedir: new option -C (default true) controls whether option
  1790 -D should include a copy of the original document directory; -C false
  1791 prevents unwanted effects such as copying of administrative CVS data.
  1792 
  1793 
  1794 *** Pure ***
  1795 
  1796 * Considerably improved version of 'constdefs' command.  Now performs
  1797 automatic type-inference of declared constants; additional support for
  1798 local structure declarations (cf. locales and HOL records), see also
  1799 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1800 sequential dependencies of definitions within a single 'constdefs'
  1801 section; moreover, the declared name needs to be an identifier.  If
  1802 all fails, consider to fall back on 'consts' and 'defs' separately.
  1803 
  1804 * Improved indexed syntax and implicit structures.  First of all,
  1805 indexed syntax provides a notational device for subscripted
  1806 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1807 expressions.  Secondly, in a local context with structure
  1808 declarations, number indexes \<^sub>n or the empty index (default
  1809 number 1) refer to a certain fixed variable implicitly; option
  1810 show_structs controls printing of implicit structures.  Typical
  1811 applications of these concepts involve record types and locales.
  1812 
  1813 * New command 'no_syntax' removes grammar declarations (and
  1814 translations) resulting from the given syntax specification, which is
  1815 interpreted in the same manner as for the 'syntax' command.
  1816 
  1817 * 'Advanced' translation functions (parse_translation etc.) may depend
  1818 on the signature of the theory context being presently used for
  1819 parsing/printing, see also isar-ref manual.
  1820 
  1821 * Improved 'oracle' command provides a type-safe interface to turn an
  1822 ML expression of type theory -> T -> term into a primitive rule of
  1823 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1824 is already included here); see also FOL/ex/IffExample.thy;
  1825 INCOMPATIBILITY.
  1826 
  1827 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1828 before); "cI" is no longer bound, use "c.intro" instead.
  1829 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1830 axclasses vs. locales.
  1831 
  1832 * Improved internal renaming of symbolic identifiers -- attach primes
  1833 instead of base 26 numbers.
  1834 
  1835 * New flag show_question_marks controls printing of leading question
  1836 marks in schematic variable names.
  1837 
  1838 * In schematic variable names, *any* symbol following \<^isub> or
  1839 \<^isup> is now treated as part of the base name.  For example, the
  1840 following works without printing of awkward ".0" indexes:
  1841 
  1842   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1843     by simp
  1844 
  1845 * Inner syntax includes (*(*nested*) comments*).
  1846 
  1847 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1848 annotations as "(00...)".
  1849 
  1850 * Clear separation of logical types and nonterminals, where the latter
  1851 may only occur in 'syntax' specifications or type abbreviations.
  1852 Before that distinction was only partially implemented via type class
  1853 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1854 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1855 exotic syntax specifications may require further adaption
  1856 (e.g. Cube/Cube.thy).
  1857 
  1858 * Removed obsolete type class "logic", use the top sort {} instead.
  1859 Note that non-logical types should be declared as 'nonterminals'
  1860 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1861 specifications.
  1862 
  1863 * Attributes 'induct' and 'cases': type or set names may now be
  1864 locally fixed variables as well.
  1865 
  1866 * Simplifier: can now control the depth to which conditional rewriting
  1867 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1868 Limit.
  1869 
  1870 * Simplifier: simplification procedures may now take the current
  1871 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1872 interface), which is very useful for calling the Simplifier
  1873 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1874 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1875 low-level mk_simproc no longer applies Logic.varify internally, to
  1876 allow for use in a context of fixed variables.
  1877 
  1878 * thin_tac now works even if the assumption being deleted contains !!
  1879 or ==>.  More generally, erule now works even if the major premise of
  1880 the elimination rule contains !! or ==>.
  1881 
  1882 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1883 
  1884 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1885 from Pure, which contains all common declarations already.  Both
  1886 theories are defined via plain Isabelle/Isar .thy files.
  1887 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1888 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1889 use isatool fixcpure to adapt your theory and ML sources.
  1890 
  1891 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1892 selections of theorems in named facts via index ranges.
  1893 
  1894 * 'print_theorems': in theory mode, really print the difference
  1895 wrt. the last state (works for interactive theory development only),
  1896 in proof mode print all local facts (cf. 'print_facts');
  1897 
  1898 * 'hide': option '(open)' hides only base names.
  1899 
  1900 * More efficient treatment of intermediate checkpoints in interactive
  1901 theory development.
  1902 
  1903 * Code generator is now invoked via code_module (incremental code
  1904 generation) and code_library (modular code generation, ML structures
  1905 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1906 must be quoted when used as identifiers.
  1907 
  1908 * New 'value' command for reading, evaluating and printing terms using
  1909 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1910 quoted when used as identifier.
  1911 
  1912 
  1913 *** Locales ***
  1914 
  1915 * New commands for the interpretation of locale expressions in
  1916 theories (1), locales (2) and proof contexts (3).  These generate
  1917 proof obligations from the expression specification.  After the
  1918 obligations have been discharged, theorems of the expression are added
  1919 to the theory, target locale or proof context.  The synopsis of the
  1920 commands is a follows:
  1921 
  1922   (1) interpretation expr inst
  1923   (2) interpretation target < expr
  1924   (3) interpret expr inst
  1925 
  1926 Interpretation in theories and proof contexts require a parameter
  1927 instantiation of terms from the current context.  This is applied to
  1928 specifications and theorems of the interpreted expression.
  1929 Interpretation in locales only permits parameter renaming through the
  1930 locale expression.  Interpretation is smart in that interpretations
  1931 that are active already do not occur in proof obligations, neither are
  1932 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1933 inspect active interpretations of a particular locale.  For details,
  1934 see the Isar Reference manual.  Examples can be found in
  1935 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1936 
  1937 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1938 'interpret' instead.
  1939 
  1940 * New context element 'constrains' for adding type constraints to
  1941 parameters.
  1942 
  1943 * Context expressions: renaming of parameters with syntax
  1944 redeclaration.
  1945 
  1946 * Locale declaration: 'includes' disallowed.
  1947 
  1948 * Proper static binding of attribute syntax -- i.e. types / terms /
  1949 facts mentioned as arguments are always those of the locale definition
  1950 context, independently of the context of later invocations.  Moreover,
  1951 locale operations (renaming and type / term instantiation) are applied
  1952 to attribute arguments as expected.
  1953 
  1954 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1955 actual attributes; rare situations may require Attrib.attribute to
  1956 embed those attributes into Attrib.src that lack concrete syntax.
  1957 Attribute implementations need to cooperate properly with the static
  1958 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1959 Attrib.XXX_thm etc. already do the right thing without further
  1960 intervention.  Only unusual applications -- such as "where" or "of"
  1961 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1962 on the context and the facts involved -- may have to assign parsed
  1963 values to argument tokens explicitly.
  1964 
  1965 * Changed parameter management in theorem generation for long goal
  1966 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1967 theorem statement in rare situations.
  1968 
  1969 * Locale inspection command 'print_locale' omits notes elements.  Use
  1970 'print_locale!' to have them included in the output.
  1971 
  1972 
  1973 *** Provers ***
  1974 
  1975 * Provers/hypsubst.ML: improved version of the subst method, for
  1976 single-step rewriting: it now works in bound variable contexts. New is
  1977 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1978 rewrite a different subterm than the original subst method, which is
  1979 still available as 'simplesubst'.
  1980 
  1981 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1982 and quasi orders.
  1983 
  1984 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1985 reflexive-transitive closure of relations.
  1986 
  1987 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1988 limit (previously hard-coded with a value of 20) user-definable.
  1989 
  1990 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1991 is peformed already.  Object-logics merely need to finish their
  1992 initial simpset configuration as before.  INCOMPATIBILITY.
  1993 
  1994 
  1995 *** HOL ***
  1996 
  1997 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1998 
  1999   syntax (epsilon)
  2000     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2001 
  2002 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2003 and x-symbol; use option '-m epsilon' to get it actually printed.
  2004 Moreover, the mathematically important symbolic identifier \<epsilon>
  2005 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2006 
  2007 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2008 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2009 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2010 support corresponding Isar calculations.
  2011 
  2012 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2013 instead of ":".
  2014 
  2015 * theory SetInterval: changed the syntax for open intervals:
  2016 
  2017   Old       New
  2018   {..n(}    {..<n}
  2019   {)n..}    {n<..}
  2020   {m..n(}   {m..<n}
  2021   {)m..n}   {m<..n}
  2022   {)m..n(}  {m<..<n}
  2023 
  2024 The old syntax is still supported but will disappear in the next
  2025 release.  For conversion use the following Emacs search and replace
  2026 patterns (these are not perfect but work quite well):
  2027 
  2028   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2029   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2030 
  2031 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2032 equalities in commutative rings; method 'algebra' provides a generic
  2033 interface.
  2034 
  2035 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2036 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2037 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2038 be a tuple pattern.
  2039 
  2040 Some new syntax forms are available:
  2041 
  2042   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2043   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2044   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2045   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2046 
  2047 The latter form "\<Sum>x < k. e" used to be based on a separate
  2048 function "Summation", which has been discontinued.
  2049 
  2050 * theory Finite_Set: in structured induction proofs, the insert case
  2051 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2052 (insert F x)'.
  2053 
  2054 * The 'refute' command has been extended to support a much larger
  2055 fragment of HOL, including axiomatic type classes, constdefs and
  2056 typedefs, inductive datatypes and recursion.
  2057 
  2058 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2059 Requires zChaff with proof generation to be installed.  See
  2060 HOL/ex/SAT_Examples.thy for examples.
  2061 
  2062 * Datatype induction via method 'induct' now preserves the name of the
  2063 induction variable. For example, when proving P(xs::'a list) by
  2064 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2065 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2066 in unstructured proof scripts.
  2067 
  2068 * Reworked implementation of records.  Improved scalability for
  2069 records with many fields, avoiding performance problems for type
  2070 inference. Records are no longer composed of nested field types, but
  2071 of nested extension types. Therefore the record type only grows linear
  2072 in the number of extensions and not in the number of fields.  The
  2073 top-level (users) view on records is preserved.  Potential
  2074 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2075 old record representation. The type generated for a record is called
  2076 <record_name>_ext_type.
  2077 
  2078 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2079 proofs triggered by a record definition or a simproc (if
  2080 quick_and_dirty is enabled).  Definitions of large records can take
  2081 quite long.
  2082 
  2083 New simproc record_upd_simproc for simplification of multiple record
  2084 updates enabled by default.  Moreover, trivial updates are also
  2085 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2086 occasionally, since simplification is more powerful by default.
  2087 
  2088 * typedef: proper support for polymorphic sets, which contain extra
  2089 type-variables in the term.
  2090 
  2091 * Simplifier: automatically reasons about transitivity chains
  2092 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2093 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2094 old proofs break occasionally as simplification may now solve more
  2095 goals than previously.
  2096 
  2097 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2098 present.  Works for all partial orders (class "order"), in particular
  2099 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2100 just like y <= x.
  2101 
  2102 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2103 bound variable or a constant then the let is unfolded.  Otherwise
  2104 first a is simplified to b, and then f b is simplified to g. If
  2105 possible we abstract b from g arriving at "let x = b in h x",
  2106 otherwise we unfold the let and arrive at g.  The simproc can be
  2107 enabled/disabled by the reference use_let_simproc.  Potential
  2108 INCOMPATIBILITY since simplification is more powerful by default.
  2109 
  2110 * Classical reasoning: the meson method now accepts theorems as arguments.
  2111 
  2112 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2113 jobs to provide advice on the provability of subgoals.
  2114 
  2115 * Theory OrderedGroup and Ring_and_Field: various additions and
  2116 improvements to faciliate calculations involving equalities and
  2117 inequalities.
  2118 
  2119 The following theorems have been eliminated or modified
  2120 (INCOMPATIBILITY):
  2121 
  2122   abs_eq             now named abs_of_nonneg
  2123   abs_of_ge_0        now named abs_of_nonneg
  2124   abs_minus_eq       now named abs_of_nonpos
  2125   imp_abs_id         now named abs_of_nonneg
  2126   imp_abs_neg_id     now named abs_of_nonpos
  2127   mult_pos           now named mult_pos_pos
  2128   mult_pos_le        now named mult_nonneg_nonneg
  2129   mult_pos_neg_le    now named mult_nonneg_nonpos
  2130   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2131   mult_neg           now named mult_neg_neg
  2132   mult_neg_le        now named mult_nonpos_nonpos
  2133 
  2134 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2135      
  2136      zero_le_square
  2137      not_square_less_zero 
  2138 
  2139   The following lemmas have been deleted from Real/RealPow:
  2140   
  2141      realpow_zero_zero
  2142      realpow_two
  2143      realpow_less
  2144      zero_le_power
  2145      realpow_two_le
  2146      abs_realpow_two
  2147      realpow_two_abs     
  2148 
  2149 * Theory Parity: added rules for simplifying exponents.
  2150 
  2151 * Theory List:
  2152 
  2153 The following theorems have been eliminated or modified
  2154 (INCOMPATIBILITY):
  2155 
  2156   list_all_Nil       now named list_all.simps(1)
  2157   list_all_Cons      now named list_all.simps(2)
  2158   list_all_conv      now named list_all_iff
  2159   set_mem_eq         now named mem_iff
  2160 
  2161 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2162 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2163 
  2164 
  2165 *** HOL-Complex ***
  2166 
  2167 * Theory RealDef: better support for embedding natural numbers and
  2168 integers in the reals.
  2169 
  2170 The following theorems have been eliminated or modified
  2171 (INCOMPATIBILITY):
  2172 
  2173   exp_ge_add_one_self  now requires no hypotheses
  2174   real_of_int_add      reversed direction of equality (use [symmetric])
  2175   real_of_int_minus    reversed direction of equality (use [symmetric])
  2176   real_of_int_diff     reversed direction of equality (use [symmetric])
  2177   real_of_int_mult     reversed direction of equality (use [symmetric])
  2178 
  2179 * Theory RComplete: expanded support for floor and ceiling functions.
  2180 
  2181 * Theory Ln is new, with properties of the natural logarithm
  2182 
  2183 * Hyperreal: There is a new type constructor "star" for making
  2184 nonstandard types.  The old type names are now type synonyms:
  2185 
  2186   hypreal = real star
  2187   hypnat = nat star
  2188   hcomplex = complex star
  2189 
  2190 * Hyperreal: Many groups of similarly-defined constants have been
  2191 replaced by polymorphic versions (INCOMPATIBILITY):
  2192 
  2193   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2194 
  2195   starset      <-- starsetNat, starsetC
  2196   *s*          <-- *sNat*, *sc*
  2197   starset_n    <-- starsetNat_n, starsetC_n
  2198   *sn*         <-- *sNatn*, *scn*
  2199   InternalSets <-- InternalNatSets, InternalCSets
  2200 
  2201   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2202   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2203   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2204   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2205   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2206 
  2207 * Hyperreal: Many type-specific theorems have been removed in favor of
  2208 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2209 
  2210   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2211   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2212   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2213   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2214   right_minus <-- hypreal_add_minus
  2215   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2216   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2217   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2218   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2219   mult_1_right <-- hcomplex_mult_one_right
  2220   mult_zero_left <-- hcomplex_mult_zero_left
  2221   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2222   right_distrib <-- hypnat_add_mult_distrib2
  2223   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2224   right_inverse <-- hypreal_mult_inverse
  2225   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2226   order_refl <-- {hypreal,hypnat}_le_refl
  2227   order_trans <-- {hypreal,hypnat}_le_trans
  2228   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2229   order_less_le <-- {hypreal,hypnat}_less_le
  2230   linorder_linear <-- {hypreal,hypnat}_le_linear
  2231   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2232   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2233   add_nonneg_nonneg <-- hypreal_le_add_order
  2234 
  2235 * Hyperreal: Separate theorems having to do with type-specific
  2236 versions of constants have been merged into theorems that apply to the
  2237 new polymorphic constants (INCOMPATIBILITY):
  2238 
  2239   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2240   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2241   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2242   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2243   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2244   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2245   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2246   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2247   STAR_diff <-- {STAR,STARC}_diff
  2248   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2249     STARC_hcomplex_of_complex}_image_subset
  2250   starset_n_Un <-- starset{Nat,C}_n_Un
  2251   starset_n_Int <-- starset{Nat,C}_n_Int
  2252   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2253   starset_n_diff <-- starset{Nat,C}_n_diff
  2254   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2255   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2256   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2257   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2258   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2259   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2260   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2261   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2262   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2263   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2264   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2265   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2266   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2267   starfun_diff <-- starfun{C,RC,CR}_diff
  2268   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2269   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2270   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2271   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2272   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2273   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2274   starfun_Id <-- starfunC_Id
  2275   starfun_approx <-- starfun{Nat,CR}_approx
  2276   starfun_capprox <-- starfun{C,RC}_capprox
  2277   starfun_abs <-- starfunNat_rabs
  2278   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2279   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2280   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2281   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2282   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2283   starfun_add_approx <-- starfunCR_add_approx
  2284   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2285   starfun_divide <-- starfun{C,CR,RC}_divide
  2286   starfun_n <-- starfun{Nat,C}_n
  2287   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2288   starfun_n_add <-- starfun{Nat,C}_n_add
  2289   starfun_n_add_minus <-- starfunNat_n_add_minus
  2290   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2291   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2292   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2293 
  2294   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2295   star_n_minus <-- {hypreal,hcomplex}_minus
  2296   star_n_diff <-- {hypreal,hcomplex}_diff
  2297   star_n_mult <-- {hypreal,hcomplex}_mult
  2298   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2299   star_n_le <-- {hypreal,hypnat}_le
  2300   star_n_less <-- {hypreal,hypnat}_less
  2301   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2302   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2303   star_n_abs <-- hypreal_hrabs
  2304   star_n_divide <-- hcomplex_divide
  2305 
  2306   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2307   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2308   star_of_diff <-- hypreal_of_real_diff
  2309   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2310   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2311   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2312   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2313   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2314   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2315   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2316   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2317   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2318   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2319   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2320   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2321   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2322   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2323   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2324   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2325   star_of_power <-- hypreal_of_real_power
  2326   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2327 
  2328 * Hyperreal: new method "transfer" that implements the transfer
  2329 principle of nonstandard analysis. With a subgoal that mentions
  2330 nonstandard types like "'a star", the command "apply transfer"
  2331 replaces it with an equivalent one that mentions only standard types.
  2332 To be successful, all free variables must have standard types; non-
  2333 standard variables must have explicit universal quantifiers.
  2334 
  2335 * Hyperreal: A theory of Taylor series.
  2336 
  2337 
  2338 *** HOLCF ***
  2339 
  2340 * Discontinued special version of 'constdefs' (which used to support
  2341 continuous functions) in favor of the general Pure one with full
  2342 type-inference.
  2343 
  2344 * New simplification procedure for solving continuity conditions; it
  2345 is much faster on terms with many nested lambda abstractions (cubic
  2346 instead of exponential time).
  2347 
  2348 * New syntax for domain package: selector names are now optional.
  2349 Parentheses should be omitted unless argument is lazy, for example:
  2350 
  2351   domain 'a stream = cons "'a" (lazy "'a stream")
  2352 
  2353 * New command 'fixrec' for defining recursive functions with pattern
  2354 matching; defining multiple functions with mutual recursion is also
  2355 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2356 sinr, or any data constructor defined by the domain package. The given
  2357 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2358 syntax and examples.
  2359 
  2360 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2361 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2362 but the proof obligation additionally includes an admissibility
  2363 requirement. The packages generate instances of class cpo or pcpo,
  2364 with continuity and strictness theorems for Rep and Abs.
  2365 
  2366 * HOLCF: Many theorems have been renamed according to a more standard naming
  2367 scheme (INCOMPATIBILITY):
  2368 
  2369   foo_inject:  "foo$x = foo$y ==> x = y"
  2370   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2371   foo_less:    "(foo$x << foo$y) = (x << y)"
  2372   foo_strict:  "foo$UU = UU"
  2373   foo_defined: "... ==> foo$x ~= UU"
  2374   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2375 
  2376 
  2377 *** ZF ***
  2378 
  2379 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2380 including the First Isomorphism Theorem (on quotienting by the kernel
  2381 of a homomorphism).
  2382 
  2383 * ZF/Simplifier: install second copy of type solver that actually
  2384 makes use of TC rules declared to Isar proof contexts (or locales);
  2385 the old version is still required for ML proof scripts.
  2386 
  2387 
  2388 *** Cube ***
  2389 
  2390 * Converted to Isar theory format; use locales instead of axiomatic
  2391 theories.
  2392 
  2393 
  2394 *** ML ***
  2395 
  2396 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2397 for ||>, ||>>, |>>,
  2398 
  2399 * Pure/library.ML no longer defines its own option datatype, but uses
  2400 that of the SML basis, which has constructors NONE and SOME instead of
  2401 None and Some, as well as exception Option.Option instead of OPTION.
  2402 The functions the, if_none, is_some, is_none have been adapted
  2403 accordingly, while Option.map replaces apsome.
  2404 
  2405 * Pure/library.ML: the exception LIST has been given up in favour of
  2406 the standard exceptions Empty and Subscript, as well as
  2407 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2408 superceded by the standard hd and tl functions etc.
  2409 
  2410 A number of basic list functions are no longer exported to the ML
  2411 toplevel, as they are variants of predefined functions.  The following
  2412 suggests how one can translate existing code:
  2413 
  2414     rev_append xs ys = List.revAppend (xs, ys)
  2415     nth_elem (i, xs) = List.nth (xs, i)
  2416     last_elem xs = List.last xs
  2417     flat xss = List.concat xss
  2418     seq fs = List.app fs
  2419     partition P xs = List.partition P xs
  2420     mapfilter f xs = List.mapPartial f xs
  2421 
  2422 * Pure/library.ML: several combinators for linear functional
  2423 transformations, notably reverse application and composition:
  2424 
  2425   x |> f                f #> g
  2426   (x, y) |-> f          f #-> g
  2427 
  2428 * Pure/library.ML: introduced/changed precedence of infix operators:
  2429 
  2430   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2431   infix 2 ?;
  2432   infix 3 o oo ooo oooo;
  2433   infix 4 ~~ upto downto;
  2434 
  2435 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2436 infix operators.
  2437 
  2438 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2439 fold_map support linear functional transformations and nesting.  For
  2440 example:
  2441 
  2442   fold f [x1, ..., xN] y =
  2443     y |> f x1 |> ... |> f xN
  2444 
  2445   (fold o fold) f [xs1, ..., xsN] y =
  2446     y |> fold f xs1 |> ... |> fold f xsN
  2447 
  2448   fold f [x1, ..., xN] =
  2449     f x1 #> ... #> f xN
  2450 
  2451   (fold o fold) f [xs1, ..., xsN] =
  2452     fold f xs1 #> ... #> fold f xsN
  2453 
  2454 * Pure/library.ML: the following selectors on type 'a option are
  2455 available:
  2456 
  2457   the:               'a option -> 'a  (*partial*)
  2458   these:             'a option -> 'a  where 'a = 'b list
  2459   the_default: 'a -> 'a option -> 'a
  2460   the_list:          'a option -> 'a list
  2461 
  2462 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2463 basic operations for association lists, following natural argument
  2464 order; moreover the explicit equality predicate passed here avoids
  2465 potentially expensive polymorphic runtime equality checks.
  2466 The old functions may be expressed as follows:
  2467 
  2468   assoc = uncurry (AList.lookup (op =))
  2469   assocs = these oo AList.lookup (op =)
  2470   overwrite = uncurry (AList.update (op =)) o swap
  2471 
  2472 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2473 
  2474   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2475   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2476 
  2477 replacing make_keylist and keyfilter (occassionally used)
  2478 Naive rewrites:
  2479 
  2480   make_keylist = AList.make
  2481   keyfilter = AList.find (op =)
  2482 
  2483 * eq_fst and eq_snd now take explicit equality parameter, thus
  2484   avoiding eqtypes. Naive rewrites:
  2485 
  2486     eq_fst = eq_fst (op =)
  2487     eq_snd = eq_snd (op =)
  2488 
  2489 * Removed deprecated apl and apr (rarely used).
  2490   Naive rewrites:
  2491 
  2492     apl (n, op) =>>= curry op n
  2493     apr (op, m) =>>= fn n => op (n, m)
  2494 
  2495 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2496 provides a reasonably efficient light-weight implementation of sets as
  2497 lists.
  2498 
  2499 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2500 few new operations; existing lookup and update are now curried to
  2501 follow natural argument order (for use with fold etc.);
  2502 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2503 
  2504 * Pure/General: output via the Isabelle channels of
  2505 writeln/warning/error etc. is now passed through Output.output, with a
  2506 hook for arbitrary transformations depending on the print_mode
  2507 (cf. Output.add_mode -- the first active mode that provides a output
  2508 function wins).  Already formatted output may be embedded into further
  2509 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2510 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2511 accommodate easy composition of diagnostic messages etc.  Programmers
  2512 rarely need to care about Output.output or Output.raw at all, with
  2513 some notable exceptions: Output.output is required when bypassing the
  2514 standard channels (writeln etc.), or in token translations to produce
  2515 properly formatted results; Output.raw is required when capturing
  2516 already output material that will eventually be presented to the user
  2517 a second time.  For the default print mode, both Output.output and
  2518 Output.raw have no effect.
  2519 
  2520 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2521 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2522 cumulative results are displayed at the end of a batch session.
  2523 
  2524 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2525 replaced by File.platform_path and File.shell_path (with appropriate
  2526 hooks).  This provides a clean interface for unusual systems where the
  2527 internal and external process view of file names are different.
  2528 
  2529 * Pure: more efficient orders for basic syntactic entities: added
  2530 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2531 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2532 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2533 orders now -- potential INCOMPATIBILITY for code that depends on a
  2534 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2535 Library.sort_strings on result).
  2536 
  2537 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2538 fold_types traverse types/terms from left to right, observing natural
  2539 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2540 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2541 
  2542 * Pure: name spaces have been refined, with significant changes of the
  2543 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2544 to extern(_table).  The plain name entry path is superceded by a
  2545 general 'naming' context, which also includes the 'policy' to produce
  2546 a fully qualified name and external accesses of a fully qualified
  2547 name; NameSpace.extend is superceded by context dependent
  2548 Sign.declare_name.  Several theory and proof context operations modify
  2549 the naming context.  Especially note Theory.restore_naming and
  2550 ProofContext.restore_naming to get back to a sane state; note that
  2551 Theory.add_path is no longer sufficient to recover from
  2552 Theory.absolute_path in particular.
  2553 
  2554 * Pure: new flags short_names (default false) and unique_names
  2555 (default true) for controlling output of qualified names.  If
  2556 short_names is set, names are printed unqualified.  If unique_names is
  2557 reset, the name prefix is reduced to the minimum required to achieve
  2558 the original result when interning again, even if there is an overlap
  2559 with earlier declarations.
  2560 
  2561 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2562 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2563 (useful for printing error messages).  INCOMPATIBILITY.
  2564 
  2565 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2566 Theory.theory are now identified, referring to the universal
  2567 Context.theory (see Pure/context.ML).  Actual signature and theory
  2568 content is managed as theory data.  The old code and interfaces were
  2569 spread over many files and structures; the new arrangement introduces
  2570 considerable INCOMPATIBILITY to gain more clarity:
  2571 
  2572   Context -- theory management operations (name, identity, inclusion,
  2573     parents, ancestors, merge, etc.), plus generic theory data;
  2574 
  2575   Sign -- logical signature and syntax operations (declaring consts,
  2576     types, etc.), plus certify/read for common entities;
  2577 
  2578   Theory -- logical theory operations (stating axioms, definitions,
  2579     oracles), plus a copy of logical signature operations (consts,
  2580     types, etc.); also a few basic management operations (Theory.copy,
  2581     Theory.merge, etc.)
  2582 
  2583 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2584 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2585 for convenience -- they merely return the theory.
  2586 
  2587 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2588 
  2589 * Pure: the Isar proof context type is already defined early in Pure
  2590 as Context.proof (note that ProofContext.context and Proof.context are
  2591 aliases, where the latter is the preferred name).  This enables other
  2592 Isabelle components to refer to that type even before Isar is present.
  2593 
  2594 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2595 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2596 any of these kinds.  For example, Sign.intern typeK is now
  2597 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2598 Theory.hide_types.  Also note that former
  2599 Theory.hide_classes/types/consts are now
  2600 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2601 internalize their arguments!  INCOMPATIBILITY.
  2602 
  2603 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2604 datatype thmref (with constructors Name and NameSelection) instead of
  2605 plain string -- INCOMPATIBILITY;
  2606 
  2607 * Pure: cases produced by proof methods specify options, where NONE
  2608 means to remove case bindings -- INCOMPATIBILITY in
  2609 (RAW_)METHOD_CASES.
  2610 
  2611 * Pure: the following operations retrieve axioms or theorems from a
  2612 theory node or theory hierarchy, respectively:
  2613 
  2614   Theory.axioms_of: theory -> (string * term) list
  2615   Theory.all_axioms_of: theory -> (string * term) list
  2616   PureThy.thms_of: theory -> (string * thm) list
  2617   PureThy.all_thms_of: theory -> (string * thm) list
  2618 
  2619 * Pure: print_tac now outputs the goal through the trace channel.
  2620 
  2621 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2622 Reference Toplevel.debug (default false) controls detailed printing
  2623 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2624 controls execution profiling -- set to 1 for time and 2 for space
  2625 (both increase the runtime).
  2626 
  2627 * Isar session: The initial use of ROOT.ML is now always timed,
  2628 i.e. the log will show the actual process times, in contrast to the
  2629 elapsed wall-clock time that the outer shell wrapper produces.
  2630 
  2631 * Simplifier: improved handling of bound variables (nameless
  2632 representation, avoid allocating new strings).  Simprocs that invoke
  2633 the Simplifier recursively should use Simplifier.inherit_bounds to
  2634 avoid local name clashes.  Failure to do so produces warnings
  2635 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2636 for further details.
  2637 
  2638 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2639 bindings for all theorems stored within a given theory; this may help
  2640 in porting non-Isar theories to Isar ones, while keeping ML proof
  2641 scripts for the time being.
  2642 
  2643 * ML operator HTML.with_charset specifies the charset begin used for
  2644 generated HTML files.  For example:
  2645 
  2646   HTML.with_charset "utf-8" use_thy "Hebrew";
  2647   HTML.with_charset "utf-8" use_thy "Chinese";
  2648 
  2649 
  2650 *** System ***
  2651 
  2652 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2653 isabelle, isatool etc.).
  2654 
  2655 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2656 isatool doc, isatool mkdir, display_drafts etc.).
  2657 
  2658 * isatool usedir: option -f allows specification of the ML file to be
  2659 used by Isabelle; default is ROOT.ML.
  2660 
  2661 * New isatool version outputs the version identifier of the Isabelle
  2662 distribution being used.
  2663 
  2664 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2665 (containing Boolean satisfiability problems) into Isabelle/HOL
  2666 theories.
  2667 
  2668 
  2669 
  2670 New in Isabelle2004 (April 2004)
  2671 --------------------------------
  2672 
  2673 *** General ***
  2674 
  2675 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2676   Replaces linorder.ML.
  2677 
  2678 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2679   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2680   (\<a>...\<z>), are now considered normal letters, and can therefore
  2681   be used anywhere where an ASCII letter (a...zA...Z) has until
  2682   now. COMPATIBILITY: This obviously changes the parsing of some
  2683   terms, especially where a symbol has been used as a binder, say
  2684   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2685   as an identifier.  Fix it by inserting a space around former
  2686   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2687   existing theory and ML files.
  2688 
  2689 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2690 
  2691 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2692   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2693   a normal (but invisible) letter. For multiple letter subscripts repeat
  2694   \<^isub> like this: x\<^isub>1\<^isub>2.
  2695 
  2696 * Pure: There are now sub-/superscripts that can span more than one
  2697   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2698   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2699   superscript. The new control characters are not identifier parts.
  2700 
  2701 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2702   content of "..." to the latex file instead of \isacntrl... . The "..."
  2703   may consist of any printable characters excluding the end bracket >.
  2704 
  2705 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2706   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2707   declare constants "final", which prevents their being given a definition
  2708   later.  It is useful for constants whose behaviour is fixed axiomatically
  2709   rather than definitionally, such as the meta-logic connectives.
  2710 
  2711 * Pure: 'instance' now handles general arities with general sorts
  2712   (i.e. intersections of classes),
  2713 
  2714 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2715   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2716   It can be changed to alter the colors/layout of generated pages.
  2717 
  2718 
  2719 *** Isar ***
  2720 
  2721 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2722   cut_tac, subgoal_tac and thin_tac:
  2723   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2724     locales are no longer forced to write Isar proof scripts.
  2725     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2726     emulations.
  2727   - INCOMPATIBILITY: names of variables to be instantiated may no
  2728     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2729     This is consistent with the instantiation attribute "where".
  2730 
  2731 * Attributes "where" and "of":
  2732   - Now take type variables of instantiated theorem into account when reading
  2733     the instantiation string.  This fixes a bug that caused instantiated
  2734     theorems to have too special types in some circumstances.
  2735   - "where" permits explicit instantiations of type variables.
  2736 
  2737 * Calculation commands "moreover" and "also" no longer interfere with
  2738   current facts ("this"), admitting arbitrary combinations with "then"
  2739   and derived forms.
  2740 
  2741 * Locales:
  2742   - Goal statements involving the context element "includes" no longer
  2743     generate theorems with internal delta predicates (those ending on
  2744     "_axioms") in the premise.
  2745     Resolve particular premise with <locale>.intro to obtain old form.
  2746   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2747     specification and "includes" elements in goal statement.
  2748   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2749     [intro?] and [elim?] (respectively) by default.
  2750   - Experimental command for instantiation of locales in proof contexts:
  2751         instantiate <label>[<attrs>]: <loc>
  2752     Instantiates locale <loc> and adds all its theorems to the current context
  2753     taking into account their attributes.  Label and attrs are optional
  2754     modifiers, like in theorem declarations.  If present, names of
  2755     instantiated theorems are qualified with <label>, and the attributes
  2756     <attrs> are applied after any attributes these theorems might have already.
  2757       If the locale has assumptions, a chained fact of the form
  2758     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2759     are derived.  The command does not support old-style locales declared
  2760     with "locale (open)".
  2761       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2762 
  2763 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2764   (Isar) contexts.
  2765 
  2766 
  2767 *** HOL ***
  2768 
  2769 * Proof import: new image HOL4 contains the imported library from
  2770   the HOL4 system with about 2500 theorems. It is imported by
  2771   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2772   can be used like any other Isabelle image.  See
  2773   HOL/Import/HOL/README for more information.
  2774 
  2775 * Simplifier:
  2776   - Much improved handling of linear and partial orders.
  2777     Reasoners for linear and partial orders are set up for type classes
  2778     "linorder" and "order" respectively, and are added to the default simpset
  2779     as solvers.  This means that the simplifier can build transitivity chains
  2780     to solve goals from the assumptions.
  2781   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2782     of blast or auto after simplification become unnecessary because the goal
  2783     is solved by simplification already.
  2784 
  2785 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2786     all proved in axiomatic type classes for semirings, rings and fields.
  2787 
  2788 * Numerics:
  2789   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2790     now formalized using the Ring_and_Field theory mentioned above.
  2791   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2792     than before, because now they are set up once in a generic manner.
  2793   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2794     Look for the general versions in Ring_and_Field (and Power if they concern
  2795     exponentiation).
  2796 
  2797 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2798 
  2799 * Records:
  2800   - Record types are now by default printed with their type abbreviation
  2801     instead of the list of all field types. This can be configured via
  2802     the reference "print_record_type_abbr".
  2803   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2804     (not enabled by default).
  2805   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2806     EX x. x = sel r to True (not enabled by default).
  2807   - Tactic "record_split_simp_tac" to split and simplify records added.
  2808 
  2809 * 'specification' command added, allowing for definition by
  2810   specification.  There is also an 'ax_specification' command that
  2811   introduces the new constants axiomatically.
  2812 
  2813 * arith(_tac) is now able to generate counterexamples for reals as well.
  2814 
  2815 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2816 
  2817 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2818   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2819 
  2820 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2821   matrix theory to linear programming.
  2822 
  2823 * Unions and Intersections:
  2824   The latex output syntax of UN and INT has been changed
  2825   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2826   i.e. the index formulae has become a subscript.
  2827   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2828 
  2829 * Unions and Intersections over Intervals:
  2830   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2831   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2832   like in normal math, and corresponding versions for < and for intersection.
  2833 
  2834 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2835   lexicographic dictonary ordering has been added as "lexord".
  2836 
  2837 * ML: the legacy theory structures Int and List have been removed. They had
  2838   conflicted with ML Basis Library structures having the same names.
  2839 
  2840 * 'refute' command added to search for (finite) countermodels.  Only works
  2841   for a fragment of HOL.  The installation of an external SAT solver is
  2842   highly recommended.  See "HOL/Refute.thy" for details.
  2843 
  2844 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2845   formulae under an assignment of free variables to random values.
  2846   In contrast to 'refute', it can deal with inductive datatypes,
  2847   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2848   for examples.
  2849 
  2850 
  2851 *** HOLCF ***
  2852 
  2853 * Streams now come with concatenation and are part of the HOLCF image
  2854 
  2855 
  2856 
  2857 New in Isabelle2003 (May 2003)
  2858 ------------------------------
  2859 
  2860 *** General ***
  2861 
  2862 * Provers/simplifier:
  2863 
  2864   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2865     Assumptions are now subject to complete mutual simplification,
  2866     not just from left to right. The simplifier now preserves
  2867     the order of assumptions.
  2868 
  2869     Potential INCOMPATIBILITY:
  2870 
  2871     -- simp sometimes diverges where the old version did
  2872        not, e.g. invoking simp on the goal
  2873 
  2874         [| P (f x); y = x; f x = f y |] ==> Q
  2875 
  2876        now gives rise to the infinite reduction sequence
  2877 
  2878         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2879 
  2880        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2881        kind of problem.
  2882 
  2883     -- Tactics combining classical reasoner and simplification (such as auto)
  2884        are also affected by this change, because many of them rely on
  2885        simp. They may sometimes diverge as well or yield a different numbers
  2886        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2887        in case of problems. Sometimes subsequent calls to the classical
  2888        reasoner will fail because a preceeding call to the simplifier too
  2889        eagerly simplified the goal, e.g. deleted redundant premises.
  2890 
  2891   - The simplifier trace now shows the names of the applied rewrite rules
  2892 
  2893   - You can limit the number of recursive invocations of the simplifier
  2894     during conditional rewriting (where the simplifie tries to solve the
  2895     conditions before applying the rewrite rule):
  2896     ML "simp_depth_limit := n"
  2897     where n is an integer. Thus you can force termination where previously
  2898     the simplifier would diverge.
  2899 
  2900   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2901 
  2902   - No longer aborts on failed congruence proof.  Instead, the
  2903     congruence is ignored.
  2904 
  2905 * Pure: New generic framework for extracting programs from constructive
  2906   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2907   as HOL/Extraction for some case studies.
  2908 
  2909 * Pure: The main goal of the proof state is no longer shown by default, only
  2910 the subgoals. This behaviour is controlled by a new flag.
  2911    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2912 (ML: Proof.show_main_goal).
  2913 
  2914 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2915 rules whose conclusion matches subgoal 1:
  2916       PG menu: Isabelle/Isar -> Show me -> matching rules
  2917 The rules are ordered by how closely they match the subgoal.
  2918 In particular, rules that solve a subgoal outright are displayed first
  2919 (or rather last, the way they are printed).
  2920 (ML: ProofGeneral.print_intros())
  2921 
  2922 * Pure: New flag trace_unify_fail causes unification to print
  2923 diagnostic information (PG: in trace buffer) when it fails. This is
  2924 useful for figuring out why single step proofs like rule, erule or
  2925 assumption failed.
  2926 
  2927 * Pure: Locale specifications now produce predicate definitions
  2928 according to the body of text (covering assumptions modulo local
  2929 definitions); predicate "loc_axioms" covers newly introduced text,
  2930 while "loc" is cumulative wrt. all included locale expressions; the
  2931 latter view is presented only on export into the global theory
  2932 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2933 on the old view without predicates;
  2934 
  2935 * Pure: predefined locales "var" and "struct" are useful for sharing
  2936 parameters (as in CASL, for example); just specify something like
  2937 ``var x + var y + struct M'' as import;
  2938 
  2939 * Pure: improved thms_containing: proper indexing of facts instead of
  2940 raw theorems; check validity of results wrt. current name space;
  2941 include local facts of proof configuration (also covers active
  2942 locales), cover fixed variables in index; may use "_" in term
  2943 specification; an optional limit for the number of printed facts may
  2944 be given (the default is 40);
  2945 
  2946 * Pure: disallow duplicate fact bindings within new-style theory files
  2947 (batch-mode only);
  2948 
  2949 * Provers: improved induct method: assumptions introduced by case
  2950 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2951 the goal statement); "foo" still refers to all facts collectively;
  2952 
  2953 * Provers: the function blast.overloaded has been removed: all constants
  2954 are regarded as potentially overloaded, which improves robustness in exchange
  2955 for slight decrease in efficiency;
  2956 
  2957 * Provers/linorder: New generic prover for transitivity reasoning over
  2958 linear orders.  Note: this prover is not efficient!
  2959 
  2960 * Isar: preview of problems to finish 'show' now produce an error
  2961 rather than just a warning (in interactive mode);
  2962 
  2963 
  2964 *** HOL ***
  2965 
  2966 * arith(_tac)
  2967 
  2968  - Produces a counter example if it cannot prove a goal.
  2969    Note that the counter example may be spurious if the goal is not a formula
  2970    of quantifier-free linear arithmetic.
  2971    In ProofGeneral the counter example appears in the trace buffer.
  2972 
  2973  - Knows about div k and mod k where k is a numeral of type nat or int.
  2974 
  2975  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2976    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2977    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2978 
  2979 * simp's arithmetic capabilities have been enhanced a bit: it now
  2980 takes ~= in premises into account (by performing a case split);
  2981 
  2982 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2983 are distributed over a sum of terms;
  2984 
  2985 * New tactic "trans_tac" and method "trans" instantiate
  2986 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2987 "<=", "<" and "=").
  2988 
  2989 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2990 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2991 
  2992 * 'typedef' command has new option "open" to suppress the set
  2993 definition;
  2994 
  2995 * functions Min and Max on finite sets have been introduced (theory
  2996 Finite_Set);
  2997 
  2998 * attribute [symmetric] now works for relations as well; it turns
  2999 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3000 
  3001 * induct over a !!-quantified statement (say !!x1..xn):
  3002   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3003 
  3004 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3005 %x. None. Warning: empty_def now refers to the previously hidden definition
  3006 of the empty set.
  3007 
  3008 * Algebra: formalization of classical algebra.  Intended as base for
  3009 any algebraic development in Isabelle.  Currently covers group theory
  3010 (up to Sylow's theorem) and ring theory (Universal Property of
  3011 Univariate Polynomials).  Contributions welcome;
  3012 
  3013 * GroupTheory: deleted, since its material has been moved to Algebra;
  3014 
  3015 * Complex: new directory of the complex numbers with numeric constants,
  3016 nonstandard complex numbers, and some complex analysis, standard and
  3017 nonstandard (Jacques Fleuriot);
  3018 
  3019 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3020 
  3021 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3022 Fleuriot);
  3023 
  3024 * Real/HahnBanach: updated and adapted to locales;
  3025 
  3026 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3027 Gray and Kramer);
  3028 
  3029 * UNITY: added the Meier-Sanders theory of progress sets;
  3030 
  3031 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3032 as abstract algorithms, instantiated to the JVM;
  3033 
  3034 * Bali: Java source language formalization. Type system, operational
  3035 semantics, axiomatic semantics. Supported language features:
  3036 classes, interfaces, objects,virtual methods, static methods,
  3037 static/instance fields, arrays, access modifiers, definite
  3038 assignment, exceptions.
  3039 
  3040 
  3041 *** ZF ***
  3042 
  3043 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3044 universe, etc.);
  3045 
  3046 * Main ZF: virtually all theories converted to new-style format;
  3047 
  3048 
  3049 *** ML ***
  3050 
  3051 * Pure: Tactic.prove provides sane interface for internal proofs;
  3052 omits the infamous "standard" operation, so this is more appropriate
  3053 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3054 
  3055 * Pure: improved error reporting of simprocs;
  3056 
  3057 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3058 up simprocs;
  3059 
  3060 
  3061 *** Document preparation ***
  3062 
  3063 * uses \par instead of \\ for line breaks in theory text. This may
  3064 shift some page breaks in large documents. To get the old behaviour
  3065 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3066 
  3067 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3068 other packages
  3069 
  3070 * \<euro> now needs package babel/greek instead of marvosym (which
  3071 broke \Rightarrow)
  3072 
  3073 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3074 textcomp package)
  3075 
  3076 
  3077 
  3078 New in Isabelle2002 (March 2002)
  3079 --------------------------------
  3080 
  3081 *** Document preparation ***
  3082 
  3083 * greatly simplified document preparation setup, including more
  3084 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3085 instructive isatool mkdir; users should basically be able to get
  3086 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3087 users may run a separate document processing stage manually like this:
  3088 "isatool usedir -D output HOL Test && isatool document Test/output";
  3089 
  3090 * theory dependency graph may now be incorporated into documents;
  3091 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3092 with \includegraphics of LaTeX;
  3093 
  3094 * proper spacing of consecutive markup elements, especially text
  3095 blocks after section headings;
  3096 
  3097 * support bold style (for single symbols only), input syntax is like
  3098 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3099 
  3100 * \<bullet> is now output as bold \cdot by default, which looks much
  3101 better in printed text;
  3102 
  3103 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3104 note that these symbols are currently unavailable in Proof General /
  3105 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3106 
  3107 * isatool latex no longer depends on changed TEXINPUTS, instead
  3108 isatool document copies the Isabelle style files to the target
  3109 location;
  3110 
  3111 
  3112 *** Isar ***
  3113 
  3114 * Pure/Provers: improved proof by cases and induction;
  3115   - 'case' command admits impromptu naming of parameters (such as
  3116     "case (Suc n)");
  3117   - 'induct' method divinates rule instantiation from the inductive
  3118     claim; no longer requires excessive ?P bindings for proper
  3119     instantiation of cases;
  3120   - 'induct' method properly enumerates all possibilities of set/type
  3121     rules; as a consequence facts may be also passed through *type*
  3122     rules without further ado;
  3123   - 'induct' method now derives symbolic cases from the *rulified*
  3124     rule (before it used to rulify cases stemming from the internal
  3125     atomized version); this means that the context of a non-atomic
  3126     statement becomes is included in the hypothesis, avoiding the
  3127     slightly cumbersome show "PROP ?case" form;
  3128   - 'induct' may now use elim-style induction rules without chaining
  3129     facts, using ``missing'' premises from the goal state; this allows
  3130     rules stemming from inductive sets to be applied in unstructured
  3131     scripts, while still benefitting from proper handling of non-atomic
  3132     statements; NB: major inductive premises need to be put first, all
  3133     the rest of the goal is passed through the induction;
  3134   - 'induct' proper support for mutual induction involving non-atomic
  3135     rule statements (uses the new concept of simultaneous goals, see
  3136     below);
  3137   - append all possible rule selections, but only use the first
  3138     success (no backtracking);
  3139   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3140   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3141   - added 'print_induct_rules' (covered by help item in recent Proof
  3142     General versions);
  3143   - moved induct/cases attributes to Pure, methods to Provers;
  3144   - generic method setup instantiated for FOL and HOL;
  3145 
  3146 * Pure: support multiple simultaneous goal statements, for example
  3147 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3148 meta-level mechanism, this acts as if several individual goals had
  3149 been stated separately; in particular common proof methods need to be
  3150 repeated in order to cover all claims; note that a single elimination
  3151 step is *not* sufficient to establish the two conjunctions, so this
  3152 fails:
  3153 
  3154   assume "A & B" then have A and B ..   (*".." fails*)
  3155 
  3156 better use "obtain" in situations as above; alternative refer to
  3157 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3158 
  3159 * Pure: proper integration with ``locales''; unlike the original
  3160 version by Florian Kammller, Isar locales package high-level proof
  3161 contexts rather than raw logical ones (e.g. we admit to include
  3162 attributes everywhere); operations on locales include merge and
  3163 rename; support for implicit arguments (``structures''); simultaneous
  3164 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3165 some examples;
  3166 
  3167 * Pure: the following commands have been ``localized'', supporting a
  3168 target locale specification "(in name)": 'lemma', 'theorem',
  3169 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3170 stored both within the locale and at the theory level (exported and
  3171 qualified by the locale name);
  3172 
  3173 * Pure: theory goals may now be specified in ``long'' form, with
  3174 ad-hoc contexts consisting of arbitrary locale elements. for example
  3175 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3176 definitions may be given, too); the result is a meta-level rule with
  3177 the context elements being discharged in the obvious way;
  3178 
  3179 * Pure: new proof command 'using' allows to augment currently used
  3180 facts after a goal statement ('using' is syntactically analogous to
  3181 'apply', but acts on the goal's facts only); this allows chained facts
  3182 to be separated into parts given before and after a claim, as in
  3183 ``from a and b have C using d and e <proof>'';
  3184 
  3185 * Pure: renamed "antecedent" case to "rule_context";
  3186 
  3187 * Pure: new 'judgment' command records explicit information about the
  3188 object-logic embedding (used by several tools internally); no longer
  3189 use hard-wired "Trueprop";
  3190 
  3191 * Pure: added 'corollary' command;
  3192 
  3193 * Pure: fixed 'token_translation' command;
  3194 
  3195 * Pure: removed obsolete 'exported' attribute;
  3196 
  3197 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3198 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3199 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3200 
  3201 * Pure: method 'atomize' presents local goal premises as object-level
  3202 statements (atomic meta-level propositions); setup controlled via
  3203 rewrite rules declarations of 'atomize' attribute; example
  3204 application: 'induct' method with proper rule statements in improper
  3205 proof *scripts*;
  3206 
  3207 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3208 now consider the syntactic context of assumptions, giving a better
  3209 chance to get type-inference of the arguments right (this is
  3210 especially important for locales);
  3211 
  3212 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3213 mode;
  3214 
  3215 * Pure/obtain: the formal conclusion "thesis", being marked as
  3216 ``internal'', may no longer be reference directly in the text;
  3217 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3218 situations;
  3219 
  3220 * Pure: generic 'sym' attribute which declares a rule both as pure
  3221 'elim?' and for the 'symmetric' operation;
  3222 
  3223 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3224 text; the fixed correlation with particular command syntax has been
  3225 discontinued;
  3226 
  3227 * Pure: new method 'rules' is particularly well-suited for proof
  3228 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3229 but often produces more compact proof terms with less detours;
  3230 
  3231 * Pure/Provers/classical: simplified integration with pure rule
  3232 attributes and methods; the classical "intro?/elim?/dest?"
  3233 declarations coincide with the pure ones; the "rule" method no longer
  3234 includes classically swapped intros; "intro" and "elim" methods no
  3235 longer pick rules from the context; also got rid of ML declarations
  3236 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3237 INCOMPATIBILITY;
  3238 
  3239 * Provers/classical: attribute 'swapped' produces classical inversions
  3240 of introduction rules;
  3241 
  3242 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3243 rules instead of full simplifier context; 'iff' attribute handles
  3244 conditional rules;
  3245 
  3246 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3247 
  3248 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3249 "(permissive)" option to recover old behavior;
  3250 
  3251 * HOL: 'inductive' no longer features separate (collective) attributes
  3252 for 'intros' (was found too confusing);
  3253 
  3254 * HOL: properly declared induction rules less_induct and
  3255 wf_induct_rule;
  3256 
  3257 
  3258 *** HOL ***
  3259 
  3260 * HOL: moved over to sane numeral syntax; the new policy is as
  3261 follows:
  3262 
  3263   - 0 and 1 are polymorphic constants, which are defined on any
  3264   numeric type (nat, int, real etc.);
  3265 
  3266   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3267   binary representation internally;
  3268 
  3269   - type nat has special constructor Suc, and generally prefers Suc 0
  3270   over 1::nat and Suc (Suc 0) over 2::nat;
  3271 
  3272 This change may cause significant problems of INCOMPATIBILITY; here
  3273 are some hints on converting existing sources:
  3274 
  3275   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3276   entities, so expressions involving "-" (unary or binary minus) need
  3277   to be spaced properly;
  3278 
  3279   - existing occurrences of "1" may need to be constraint "1::nat" or
  3280   even replaced by Suc 0; similar for old "2";
  3281 
  3282   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3283 
  3284   - remove all special provisions on numerals in proofs;
  3285 
  3286 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3287 representation (depends on bin_arith_simps in the default context);
  3288 
  3289 * HOL: symbolic syntax for x^2 (numeral 2);
  3290 
  3291 * HOL: the class of all HOL types is now called "type" rather than
  3292 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3293 in axclass/classes, instance/arities, and (usually rare) occurrences
  3294 in typings (of consts etc.); internally the class is called
  3295 "HOL.type", ML programs should refer to HOLogic.typeS;
  3296 
  3297 * HOL/record package improvements:
  3298   - new derived operations "fields" to build a partial record section,
  3299     "extend" to promote a fixed record to a record scheme, and
  3300     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3301     declared as simp by default;
  3302   - shared operations ("more", "fields", etc.) now need to be always
  3303     qualified) --- potential INCOMPATIBILITY;
  3304   - removed "make_scheme" operations (use "make" with "extend") --
  3305     INCOMPATIBILITY;
  3306   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3307   - provides cases/induct rules for use with corresponding Isar
  3308     methods (for concrete records, record schemes, concrete more
  3309     parts, and schematic more parts -- in that order);
  3310   - internal definitions directly based on a light-weight abstract
  3311     theory of product types over typedef rather than datatype;
  3312 
  3313 * HOL: generic code generator for generating executable ML code from
  3314 specifications; specific support for HOL constructs such as inductive
  3315 datatypes and sets, as well as recursive functions; can be invoked
  3316 via 'generate_code' theory section;
  3317 
  3318 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3319 
  3320 * HOL: consolidated and renamed several theories.  In particular:
  3321         Ord.thy has been absorbed into HOL.thy
  3322         String.thy has been absorbed into List.thy
  3323 
  3324 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3325 (beware of argument permutation!);
  3326 
  3327 * HOL: linorder_less_split superseded by linorder_cases;
  3328 
  3329 * HOL/List: "nodups" renamed to "distinct";
  3330 
  3331 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3332 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3333   - Ex_def has changed, now need to use some_eq_ex
  3334 
  3335 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3336 in this (rare) case use:
  3337 
  3338   delSWrapper "split_all_tac"
  3339   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3340 
  3341 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3342 MAY FAIL;
  3343 
  3344 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3345 Isabelle's type classes, ^ on functions and relations has too general
  3346 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3347 necessary to attach explicit type constraints;
  3348 
  3349 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3350 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3351 renamed accordingly (eg "compI" -> "rel_compI").
  3352 
  3353 * HOL: syntax translations now work properly with numerals and records
  3354 expressions;
  3355 
  3356 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3357 of "lam" -- INCOMPATIBILITY;
  3358 
  3359 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3360 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3361 renamed "Product_Type.unit";
  3362 
  3363 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3364 
  3365 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3366 the "cases" method);
  3367 
  3368 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3369 Florian Kammller);
  3370 
  3371 * HOL/IMP: updated and converted to new-style theory format; several
  3372 parts turned into readable document, with proper Isar proof texts and
  3373 some explanations (by Gerwin Klein);
  3374 
  3375 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3376 
  3377 * HOL-Hyperreal is now a logic image;
  3378 
  3379 
  3380 *** HOLCF ***
  3381 
  3382 * Isar: consts/constdefs supports mixfix syntax for continuous
  3383 operations;
  3384 
  3385 * Isar: domain package adapted to new-style theory format, e.g. see
  3386 HOLCF/ex/Dnat.thy;
  3387 
  3388 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3389 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3390 lift.induct_tac, always use UU instead of Undef;
  3391 
  3392 * HOLCF/IMP: updated and converted to new-style theory;
  3393 
  3394 
  3395 *** ZF ***
  3396 
  3397 * Isar: proper integration of logic-specific tools and packages,
  3398 including theory commands '(co)inductive', '(co)datatype',
  3399 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3400 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3401 
  3402 * theory Main no longer includes AC; for the Axiom of Choice, base
  3403 your theory on Main_ZFC;
  3404 
  3405 * the integer library now covers quotients and remainders, with many
  3406 laws relating division to addition, multiplication, etc.;
  3407 
  3408 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3409 typeless version of the formalism;
  3410 
  3411 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3412 format;
  3413 
  3414 * ZF/Induct: new directory for examples of inductive definitions,
  3415 including theory Multiset for multiset orderings; converted to
  3416 new-style theory format;
  3417 
  3418 * ZF: many new theorems about lists, ordinals, etc.;
  3419 
  3420 
  3421 *** General ***
  3422 
  3423 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3424 variable proof controls level of detail: 0 = no proofs (only oracle
  3425 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3426 also ref manual for further ML interfaces;
  3427 
  3428 * Pure/axclass: removed obsolete ML interface
  3429 goal_subclass/goal_arity;
  3430 
  3431 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3432 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3433 separate tokens, so expressions involving minus need to be spaced
  3434 properly;
  3435 
  3436 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3437 rather than "infixl" or "infixr";
  3438 
  3439 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3440 sort constraint specifications in type inference; e.g. "x::_::foo"
  3441 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3442 type variable);
  3443 
  3444 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3445 control output of nested => (types); the default behavior is
  3446 "type_brackets";
  3447 
  3448 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3449 tokens into AST constants;
  3450 
  3451 * Pure/syntax: prefer later declarations of translations and print
  3452 translation functions; potential INCOMPATIBILITY: need to reverse
  3453 multiple declarations for same syntax element constant;
  3454 
  3455 * Pure/show_hyps reset by default (in accordance to existing Isar
  3456 practice);
  3457 
  3458 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3459 addSafter;
  3460 
  3461 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3462 as well;
  3463 
  3464 * system: tested support for MacOS X; should be able to get Isabelle +
  3465 Proof General to work in a plain Terminal after installing Poly/ML
  3466 (e.g. from the Isabelle distribution area) and GNU bash alone
  3467 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3468 support requires further installations, e.g. from
  3469 http://fink.sourceforge.net/);
  3470 
  3471 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3472 
  3473 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3474 of 40 MB), cf. ML_OPTIONS;
  3475 
  3476 * system: Proof General keywords specification is now part of the
  3477 Isabelle distribution (see etc/isar-keywords.el);
  3478 
  3479 * system: support for persistent Proof General sessions (refrain from
  3480 outdating all loaded theories on startup); user may create writable
  3481 logic images like this: ``isabelle -q HOL Test'';
  3482 
  3483 * system: smart selection of Isabelle process versus Isabelle
  3484 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3485 run both "isabelle" and "Isabelle" even if file names are badly
  3486 damaged (executable inspects the case of the first letter of its own
  3487 name); added separate "isabelle-process" and "isabelle-interface";
  3488 
  3489 * system: refrain from any attempt at filtering input streams; no
  3490 longer support ``8bit'' encoding of old isabelle font, instead proper
  3491 iso-latin characters may now be used; the related isatools
  3492 "symbolinput" and "nonascii" have disappeared as well;
  3493 
  3494 * system: removed old "xterm" interface (the print modes "xterm" and
  3495 "xterm_color" are still available for direct use in a suitable
  3496 terminal);
  3497 
  3498 
  3499 
  3500 New in Isabelle99-2 (February 2001)
  3501 -----------------------------------
  3502 
  3503 *** Overview of INCOMPATIBILITIES ***
  3504 
  3505 * HOL: please note that theories in the Library and elsewhere often use the
  3506 new-style (Isar) format; to refer to their theorems in an ML script you must
  3507 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3508 
  3509 * HOL: inductive package no longer splits induction rule aggressively,
  3510 but only as far as specified by the introductions given; the old
  3511 format may be recovered via ML function complete_split_rule or attribute
  3512 'split_rule (complete)';
  3513 
  3514 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3515 gfp_Tarski to gfp_unfold;
  3516 
  3517 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3518 
  3519 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3520 relation); infix "^^" has been renamed "``"; infix "``" has been
  3521 renamed "`"; "univalent" has been renamed "single_valued";
  3522 
  3523 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3524 operation;
  3525 
  3526 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3527 
  3528 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3529 
  3530 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3531 consequence, it is no longer monotonic wrt. the local goal context
  3532 (which is now passed through the inductive cases);
  3533 
  3534 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3535 \<gg> to \<ggreater>;
  3536 
  3537 
  3538 *** Document preparation ***
  3539 
  3540 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3541 available: are "it" for near math-mode best-style output, "sl" for
  3542 slanted text style, and "tt" for plain type-writer; if no
  3543 \isabellestyle command is given, output is according to slanted
  3544 type-writer);
  3545 
  3546 * support sub/super scripts (for single symbols only), input syntax is
  3547 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3548 
  3549 * some more standard symbols; see Appendix A of the system manual for
  3550 the complete list of symbols defined in isabellesym.sty;
  3551 
  3552 * improved isabelle style files; more abstract symbol implementation
  3553 (should now use \isamath{...} and \isatext{...} in custom symbol
  3554 definitions);
  3555 
  3556 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3557 state; Note that presentation of goal states does not conform to
  3558 actual human-readable proof documents.  Please do not include goal
  3559 states into document output unless you really know what you are doing!
  3560 
  3561 * proper indentation of antiquoted output with proportional LaTeX
  3562 fonts;
  3563 
  3564 * no_document ML operator temporarily disables LaTeX document
  3565 generation;
  3566 
  3567 * isatool unsymbolize tunes sources for plain ASCII communication;
  3568 
  3569 
  3570 *** Isar ***
  3571 
  3572 * Pure: Isar now suffers initial goal statements to contain unbound
  3573 schematic variables (this does not conform to actual readable proof
  3574 documents, due to unpredictable outcome and non-compositional proof
  3575 checking); users who know what they are doing may use schematic goals
  3576 for Prolog-style synthesis of proven results;
  3577 
  3578 * Pure: assumption method (an implicit finishing) now handles actual
  3579 rules as well;
  3580 
  3581 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3582 initial goal, declare "that" only as Pure intro (only for single
  3583 steps); the "that" rule assumption may now be involved in implicit
  3584 finishing, thus ".." becomes a feasible for trivial obtains;
  3585 
  3586 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3587 instance proofs may be performed by "..";
  3588 
  3589 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3590 statements as well;
  3591 
  3592 * Pure: more robust selection of calculational rules;
  3593 
  3594 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3595 rule (as well as the assumption rule);
  3596 
  3597 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3598 lemmas, using the graph browser tool;
  3599 
  3600 * Pure: predict failure of "show" in interactive mode;
  3601 
  3602 * Pure: 'thms_containing' now takes actual terms as arguments;
  3603 
  3604 * HOL: improved method 'induct' --- now handles non-atomic goals
  3605 (potential INCOMPATIBILITY); tuned error handling;
  3606 
  3607 * HOL: cases and induct rules now provide explicit hints about the
  3608 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3609 any remaining facts are inserted into the goal verbatim;
  3610 
  3611 * HOL: local contexts (aka cases) may now contain term bindings as
  3612 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3613 the result to be shown in each case;
  3614 
  3615 * HOL: added 'recdef_tc' command;
  3616 
  3617 * isatool convert assists in eliminating legacy ML scripts;
  3618 
  3619 
  3620 *** HOL ***
  3621 
  3622 * HOL/Library: a collection of generic theories to be used together
  3623 with main HOL; the theory loader path already includes this directory
  3624 by default; the following existing theories have been moved here:
  3625 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3626 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3627 
  3628 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3629 modelling and verification task performed in Isabelle/HOL +
  3630 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3631 
  3632 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3633 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3634 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3635 'domain', this makes the theory consistent with mathematical
  3636 literature;
  3637 
  3638 * HOL basics: added overloaded operations "inverse" and "divide"
  3639 (infix "/"), syntax for generic "abs" operation, generic summation
  3640 operator \<Sum>;
  3641 
  3642 * HOL/typedef: simplified package, provide more useful rules (see also
  3643 HOL/subset.thy);
  3644 
  3645 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3646 now expressed as a proper nested rule (old-style tactic scripts may
  3647 require atomize_strip_tac to cope with non-atomic premises);
  3648 
  3649 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3650 to "split_conv" (old name still available for compatibility);
  3651 
  3652 * HOL: improved concrete syntax for strings (e.g. allows translation
  3653 rules with string literals);
  3654 
  3655 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3656  and Fleuriot's mechanization of analysis, including the transcendental
  3657  functions for the reals;
  3658 
  3659 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3660 
  3661 
  3662 *** CTT ***
  3663 
  3664 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3665 "lam" is displayed as TWO lambda-symbols
  3666 
  3667 * CTT: theory Main now available, containing everything (that is, Bool
  3668 and Arith);
  3669 
  3670 
  3671 *** General ***
  3672 
  3673 * Pure: the Simplifier has been implemented properly as a derived rule
  3674 outside of the actual kernel (at last!); the overall performance
  3675 penalty in practical applications is about 50%, while reliability of
  3676 the Isabelle inference kernel has been greatly improved;
  3677 
  3678 * print modes "brackets" and "no_brackets" control output of nested =>
  3679 (types) and ==> (props); the default behaviour is "brackets";
  3680 
  3681 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3682 as assumptions as well;
  3683 
  3684 * system: support Poly/ML 4.0;
  3685 
  3686 * system: isatool install handles KDE version 1 or 2;
  3687 
  3688 
  3689 
  3690 New in Isabelle99-1 (October 2000)
  3691 ----------------------------------
  3692 
  3693 *** Overview of INCOMPATIBILITIES ***
  3694 
  3695 * HOL: simplification of natural numbers is much changed; to partly
  3696 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3697 issue the following ML commands:
  3698 
  3699   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3700   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3701 
  3702 * HOL: simplification no longer dives into case-expressions; this is
  3703 controlled by "t.weak_case_cong" for each datatype t;
  3704 
  3705 * HOL: nat_less_induct renamed to less_induct;
  3706 
  3707 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3708 fixsome to patch .thy and .ML sources automatically;
  3709 
  3710   select_equality  -> some_equality
  3711   select_eq_Ex     -> some_eq_ex
  3712   selectI2EX       -> someI2_ex
  3713   selectI2         -> someI2
  3714   selectI          -> someI
  3715   select1_equality -> some1_equality
  3716   Eps_sym_eq       -> some_sym_eq_trivial
  3717   Eps_eq           -> some_eq_trivial
  3718 
  3719 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3720 
  3721 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3722 instead);
  3723 
  3724 * HOL: the recursion equations generated by 'recdef' are now called
  3725 f.simps instead of f.rules;
  3726 
  3727 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3728 
  3729 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3730 sometimes be needed;
  3731 
  3732 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3733 
  3734 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3735 
  3736 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3737 product is now "<*>" instead of "Times"; the lexicographic product is
  3738 now "<*lex*>" instead of "**";
  3739 
  3740 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3741 of main HOL, but was unused); better use HOL's datatype package;
  3742 
  3743 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3744 the old syntax may be recovered as follows:
  3745 
  3746   syntax (symbols)
  3747     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3748       (infixl "\\<oplus>" 100)
  3749 
  3750 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3751 
  3752 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3753 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3754 internally;
  3755 
  3756 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3757 changed from A/r to A//r;
  3758 
  3759 * ZF: new treatment of arithmetic (nat & int) may break some old
  3760 proofs;
  3761 
  3762 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3763 rulify -> rule_format, elimify -> elim_format, ...);
  3764 
  3765 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3766 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3767 should have to change intro!! to intro? only); replaced "delrule" by
  3768 "rule del";
  3769 
  3770 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3771 
  3772 * Provers: strengthened force_tac by using new first_best_tac;
  3773 
  3774 * LaTeX document preparation: several changes of isabelle.sty (see
  3775 lib/texinputs);
  3776 
  3777 
  3778 *** Document preparation ***
  3779 
  3780 * formal comments (text blocks etc.) in new-style theories may now
  3781 contain antiquotations of thm/prop/term/typ/text to be presented
  3782 according to latex print mode; concrete syntax is like this:
  3783 @{term[show_types] "f(x) = a + x"};
  3784 
  3785 * isatool mkdir provides easy setup of Isabelle session directories,
  3786 including proper document sources;
  3787 
  3788 * generated LaTeX sources are now deleted after successful run
  3789 (isatool document -c); may retain a copy somewhere else via -D option
  3790 of isatool usedir;
  3791 
  3792 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3793 style files, achieving self-contained LaTeX sources and simplifying
  3794 LaTeX debugging;
  3795 
  3796 * old-style theories now produce (crude) LaTeX output as well;
  3797 
  3798 * browser info session directories are now self-contained (may be put
  3799 on WWW server seperately); improved graphs of nested sessions; removed
  3800 graph for 'all sessions';
  3801 
  3802 * several improvements in isabelle style files; \isabellestyle{it}
  3803 produces fake math mode output; \isamarkupheader is now \section by
  3804 default; see lib/texinputs/isabelle.sty etc.;
  3805 
  3806 
  3807 *** Isar ***
  3808 
  3809 * Isar/Pure: local results and corresponding term bindings are now
  3810 subject to Hindley-Milner polymorphism (similar to ML); this
  3811 accommodates incremental type-inference very nicely;
  3812 
  3813 * Isar/Pure: new derived language element 'obtain' supports
  3814 generalized existence reasoning;
  3815 
  3816 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3817 support accumulation of results, without applying any rules yet;
  3818 useful to collect intermediate results without explicit name
  3819 references, and for use with transitivity rules with more than 2
  3820 premises;
  3821 
  3822 * Isar/Pure: scalable support for case-analysis type proofs: new
  3823 'case' language element refers to local contexts symbolically, as
  3824 produced by certain proof methods; internally, case names are attached
  3825 to theorems as "tags";
  3826 
  3827 * Isar/Pure: theory command 'hide' removes declarations from
  3828 class/type/const name spaces;
  3829 
  3830 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3831 indicate potential overloading;
  3832 
  3833 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3834 
  3835 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3836 "{a,b,c}" instead of {a,b,c};
  3837 
  3838 * Isar/Pure now provides its own version of intro/elim/dest
  3839 attributes; useful for building new logics, but beware of confusion
  3840 with the version in Provers/classical;
  3841 
  3842 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3843 case name 'antecedent';
  3844 
  3845 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3846 to the current context is now done automatically);
  3847 
  3848 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3849 for definining proof methods in ML;
  3850 
  3851 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3852 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3853 most cases, one should have to change intro!! to intro? only);
  3854 replaced "delrule" by "rule del";
  3855 
  3856 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3857 'symmetric' attribute (the latter supercedes [RS sym]);
  3858 
  3859 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3860 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3861 well (including splits);
  3862 
  3863 * Isar/Provers: Simplifier and Classical methods now support all kind
  3864 of modifiers used in the past, including 'cong', 'iff', etc.
  3865 
  3866 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3867 of Simplifier and Classical reasoner);
  3868 
  3869 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3870 now support named cases; major packages (inductive, datatype, primrec,
  3871 recdef) support case names and properly name parameters;
  3872 
  3873 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3874 monotonicity conditions are extracted to be proven at end of
  3875 calculations;
  3876 
  3877 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3878 method anyway;
  3879 
  3880 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3881 split_if split_if_asm; datatype package provides theorems foo.splits =
  3882 foo.split foo.split_asm for each datatype;
  3883 
  3884 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3885 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3886 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3887 use "(cases (simplified))" method in proper proof texts);
  3888 
  3889 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3890 
  3891 * Isar: names of theorems etc. may be natural numbers as well;
  3892 
  3893 * Isar: 'pr' command: optional arguments for goals_limit and
  3894 ProofContext.prems_limit; no longer prints theory contexts, but only
  3895 proof states;
  3896 
  3897 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3898 additional print modes to be specified; e.g. "pr(latex)" will print
  3899 proof state according to the Isabelle LaTeX style;
  3900 
  3901 * Isar: improved support for emulating tactic scripts, including proof
  3902 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3903 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3904 (for HOL datatypes);
  3905 
  3906 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3907 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3908 'proof method scripts' have to be in depth-first order;
  3909 
  3910 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3911 
  3912 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3913 should instead use individual commands for printing items
  3914 (print_commands, print_methods etc.);
  3915 
  3916 * Isar: added 'nothing' --- the empty list of theorems;
  3917 
  3918 
  3919 *** HOL ***
  3920 
  3921 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3922 corresponding virtual machine and a specification of its bytecode
  3923 verifier and a lightweight bytecode verifier, including proofs of
  3924 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3925 Cornelia Pusch (see also the homepage of project Bali at
  3926 http://isabelle.in.tum.de/Bali/);
  3927 
  3928 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3929 Clemens Ballarin;
  3930 
  3931 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3932 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3933 Rasmussen;
  3934 
  3935 * HOL/Lattice: fundamental concepts of lattice theory and order
  3936 structures, including duals, properties of bounds versus algebraic
  3937 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3938 Theorem for complete lattices etc.; may also serve as a demonstration
  3939 for abstract algebraic reasoning using axiomatic type classes, and
  3940 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3941 
  3942 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3943 von Oheimb;
  3944 
  3945 * HOL/IMPP: extension of IMP with local variables and mutually
  3946 recursive procedures, by David von Oheimb;
  3947 
  3948 * HOL/Lambda: converted into new-style theory and document;
  3949 
  3950 * HOL/ex/Multiquote: example of multiple nested quotations and
  3951 anti-quotations -- basically a generalized version of de-Bruijn
  3952 representation; very useful in avoiding lifting of operations;
  3953 
  3954 * HOL/record: added general record equality rule to simpset; fixed
  3955 select-update simplification procedure to handle extended records as
  3956 well; admit "r" as field name;
  3957 
  3958 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3959 other numeric types and also as the identity of groups, rings, etc.;
  3960 
  3961 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3962 Types nat and int belong to this axclass;
  3963 
  3964 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3965    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3966    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3967   two terms #m*u and #n*u are replaced by #(m+n)*u
  3968     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3969   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3970     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3971 
  3972 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3973 powerful prover for predicate logic but knows nothing of clasets; see
  3974 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3975 
  3976 * HOL: new version of "case_tac" subsumes both boolean case split and
  3977 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3978 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3979 
  3980 * HOL: simplification no longer dives into case-expressions: only the
  3981 selector expression is simplified, but not the remaining arms; to
  3982 enable full simplification of case-expressions for datatype t, you may
  3983 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3984 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3985 
  3986 * HOL/recdef: the recursion equations generated by 'recdef' for
  3987 function 'f' are now called f.simps instead of f.rules; if all
  3988 termination conditions are proved automatically, these simplification
  3989 rules are added to the simpset, as in primrec; rules may be named
  3990 individually as well, resulting in a separate list of theorems for
  3991 each equation;
  3992 
  3993 * HOL/While is a new theory that provides a while-combinator. It
  3994 permits the definition of tail-recursive functions without the
  3995 provision of a termination measure. The latter is necessary once the
  3996 invariant proof rule for while is applied.
  3997 
  3998 * HOL: new (overloaded) notation for the set of elements below/above
  3999 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4000 
  4001 * HOL: theorems impI, allI, ballI bound as "strip";
  4002 
  4003 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4004 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4005 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4006 
  4007 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4008 
  4009 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4010 main HOL, but was unused);
  4011 
  4012 * HOL: fewer consts declared as global (e.g. have to refer to
  4013 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4014 
  4015 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4016 in case of overlap with user translations (e.g. judgements over
  4017 tuples); (note that the underlying logical represenation is still
  4018 bogus);
  4019 
  4020 
  4021 *** ZF ***
  4022 
  4023 * ZF: simplification automatically cancels common terms in arithmetic
  4024 expressions over nat and int;
  4025 
  4026 * ZF: new treatment of nat to minimize type-checking: all operators
  4027 coerce their operands to a natural number using the function natify,
  4028 making the algebraic laws unconditional;
  4029 
  4030 * ZF: as above, for int: operators coerce their operands to an integer
  4031 using the function intify;
  4032 
  4033 * ZF: the integer library now contains many of the usual laws for the
  4034 orderings, including $<=, and monotonicity laws for $+ and $*;
  4035 
  4036 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4037 simplification;
  4038 
  4039 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4040 to the simplifier and classical reasoner simultaneously;
  4041 
  4042 
  4043 *** General ***
  4044 
  4045 * Provers: blast_tac now handles actual object-logic rules as
  4046 assumptions; note that auto_tac uses blast_tac internally as well;
  4047 
  4048 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4049 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4050 
  4051 * Provers: delrules now handles destruct rules as well (no longer need
  4052 explicit make_elim);
  4053 
  4054 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4055   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4056 use instead the strong form,
  4057   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4058 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4059 from destruct-rules;
  4060 
  4061 * Provers: Simplifier.easy_setup provides a fast path to basic
  4062 Simplifier setup for new object-logics;
  4063 
  4064 * Pure: AST translation rules no longer require constant head on LHS;
  4065 
  4066 * Pure: improved name spaces: ambiguous output is qualified; support
  4067 for hiding of names;
  4068 
  4069 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4070 XSYMBOL_HOME; no longer need to do manual configuration in most
  4071 situations;
  4072 
  4073 * system: compression of ML heaps images may now be controlled via -c
  4074 option of isabelle and isatool usedir (currently only observed by
  4075 Poly/ML);
  4076 
  4077 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4078 useful for remote X11);
  4079 
  4080 * system: provide TAGS file for Isabelle sources;
  4081 
  4082 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4083 order;
  4084 
  4085 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4086 timing flag supersedes proof_timing and Toplevel.trace;
  4087 
  4088 * ML: new combinators |>> and |>>> for incremental transformations
  4089 with secondary results (e.g. certain theory extensions):
  4090 
  4091 * ML: PureThy.add_defs gets additional argument to indicate potential
  4092 overloading (usually false);
  4093 
  4094 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4095 results;
  4096 
  4097 
  4098 
  4099 New in Isabelle99 (October 1999)
  4100 --------------------------------
  4101 
  4102 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4103 
  4104 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4105 are no longer simplified.  (This allows the simplifier to unfold recursive
  4106 functional programs.)  To restore the old behaviour, declare
  4107 
  4108     Delcongs [if_weak_cong];
  4109 
  4110 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4111 complement;
  4112 
  4113 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4114 
  4115 * HOL/datatype: mutual_induct_tac no longer exists --
  4116   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4117 
  4118 * HOL/typedef: fixed type inference for representing set; type
  4119 arguments now have to occur explicitly on the rhs as type constraints;
  4120 
  4121 * ZF: The con_defs part of an inductive definition may no longer refer
  4122 to constants declared in the same theory;
  4123 
  4124 * HOL, ZF: the function mk_cases, generated by the inductive
  4125 definition package, has lost an argument.  To simplify its result, it
  4126 uses the default simpset instead of a supplied list of theorems.
  4127 
  4128 * HOL/List: the constructors of type list are now Nil and Cons;
  4129 
  4130 * Simplifier: the type of the infix ML functions
  4131         setSSolver addSSolver setSolver addSolver
  4132 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4133 for packaging solvers. A solver is created via
  4134         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4135 where the string argument is only a comment.
  4136 
  4137 
  4138 *** Proof tools ***
  4139 
  4140 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4141 decision procedure for linear arithmetic. Currently it is used for
  4142 types `nat', `int', and `real' in HOL (see below); it can, should and
  4143 will be instantiated for other types and logics as well.
  4144 
  4145 * The simplifier now accepts rewrite rules with flexible heads, eg
  4146      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4147   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4148   matching.
  4149 
  4150 
  4151 *** General ***
  4152 
  4153 * New Isabelle/Isar subsystem provides an alternative to traditional
  4154 tactical theorem proving; together with the ProofGeneral/isar user
  4155 interface it offers an interactive environment for developing human
  4156 readable proof documents (Isar == Intelligible semi-automated
  4157 reasoning); for further information see isatool doc isar-ref,
  4158 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4159 
  4160 * improved and simplified presentation of theories: better HTML markup
  4161 (including colors), graph views in several sizes; isatool usedir now
  4162 provides a proper interface for user theories (via -P option); actual
  4163 document preparation based on (PDF)LaTeX is available as well (for
  4164 new-style theories only); see isatool doc system for more information;
  4165 
  4166 * native support for Proof General, both for classic Isabelle and
  4167 Isabelle/Isar;
  4168 
  4169 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4170 using the graph browser tool;
  4171 
  4172 * Isabelle manuals now also available as PDF;
  4173 
  4174 * theory loader rewritten from scratch (may not be fully
  4175 bug-compatible); old loadpath variable has been replaced by show_path,
  4176 add_path, del_path, reset_path functions; new operations such as
  4177 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4178 isatool doc ref);
  4179 
  4180 * improved isatool install: option -k creates KDE application icon,
  4181 option -p DIR installs standalone binaries;
  4182 
  4183 * added ML_PLATFORM setting (useful for cross-platform installations);
  4184 more robust handling of platform specific ML images for SML/NJ;
  4185 
  4186 * the settings environment is now statically scoped, i.e. it is never
  4187 created again in sub-processes invoked from isabelle, isatool, or
  4188 Isabelle;
  4189 
  4190 * path element specification '~~' refers to '$ISABELLE_HOME';
  4191 
  4192 * in locales, the "assumes" and "defines" parts may be omitted if
  4193 empty;
  4194 
  4195 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4196 long arrows);
  4197 
  4198 * new print_mode "HTML";
  4199 
  4200 * new flag show_tags controls display of tags of theorems (which are
  4201 basically just comments that may be attached by some tools);
  4202 
  4203 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4204 mode and goal output format:
  4205 
  4206 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4207 244c244
  4208 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4209 ---
  4210 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4211 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4212 181c181
  4213 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4214 ---
  4215 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4216 
  4217 * function bind_thms stores lists of theorems (cf. bind_thm);
  4218 
  4219 * new shorthand tactics ftac, eatac, datac, fatac;
  4220 
  4221 * qed (and friends) now accept "" as result name; in that case the
  4222 theorem is not stored, but proper checks and presentation of the
  4223 result still apply;
  4224 
  4225 * theorem database now also indexes constants "Trueprop", "all",
  4226 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4227 
  4228 
  4229 *** HOL ***
  4230 
  4231 ** HOL arithmetic **
  4232 
  4233 * There are now decision procedures for linear arithmetic over nat and
  4234 int:
  4235 
  4236 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4237 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4238 are treated as atomic; subformulae not involving type `nat' or `int'
  4239 are ignored; quantified subformulae are ignored unless they are
  4240 positive universal or negative existential. The tactic has to be
  4241 invoked by hand and can be a little bit slow. In particular, the
  4242 running time is exponential in the number of occurrences of `min' and
  4243 `max', and `-' on `nat'.
  4244 
  4245 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4246 (negated) (in)equalities among the premises and the conclusion into
  4247 account (i.e. no compound formulae) and does not know about `min' and
  4248 `max', and `-' on `nat'. It is fast and is used automatically by the
  4249 simplifier.
  4250 
  4251 NB: At the moment, these decision procedures do not cope with mixed
  4252 nat/int formulae where the two parts interact, such as `m < n ==>
  4253 int(m) < int(n)'.
  4254 
  4255 * HOL/Numeral provides a generic theory of numerals (encoded
  4256 efficiently as bit strings); setup for types nat/int/real is in place;
  4257 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4258 int, existing theories and proof scripts may require a few additional
  4259 type constraints;
  4260 
  4261 * integer division and remainder can now be performed on constant
  4262 arguments;
  4263 
  4264 * many properties of integer multiplication, division and remainder
  4265 are now available;
  4266 
  4267 * An interface to the Stanford Validity Checker (SVC) is available through the
  4268 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4269 are proved automatically.  SVC must be installed separately, and its results
  4270 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4271 invocation of the underlying oracle).  For SVC see
  4272   http://verify.stanford.edu/SVC
  4273 
  4274 * IsaMakefile: the HOL-Real target now builds an actual image;
  4275 
  4276 
  4277 ** HOL misc **
  4278 
  4279 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4280 (in Isabelle/Isar) -- by Gertrud Bauer;
  4281 
  4282 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4283 analysis for assembly languages with subtypes;
  4284 
  4285 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4286 -- avoids syntactic ambiguities and treats state, transition, and
  4287 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4288 changed syntax and (many) tactics;
  4289 
  4290 * HOL/inductive: Now also handles more general introduction rules such
  4291   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4292   theorems are now maintained within the theory (maintained via the
  4293   "mono" attribute);
  4294 
  4295 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4296   (using function types) such as
  4297 
  4298   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4299 
  4300 * HOL/record: record_simproc (part of the default simpset) takes care
  4301 of selectors applied to updated records; record_split_tac is no longer
  4302 part of the default claset; update_defs may now be removed from the
  4303 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4304 
  4305   claset_ref () := claset() addSWrapper record_split_wrapper;
  4306   Delsimprocs [record_simproc]
  4307 
  4308 * HOL/typedef: fixed type inference for representing set; type
  4309 arguments now have to occur explicitly on the rhs as type constraints;
  4310 
  4311 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4312 names rather than an ML expression;
  4313 
  4314 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4315 supplied later.  Program schemes can be defined, such as
  4316     "While B C s = (if B s then While B C (C s) else s)"
  4317 where the well-founded relation can be chosen after B and C have been given.
  4318 
  4319 * HOL/List: the constructors of type list are now Nil and Cons;
  4320 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4321 course, ML tools referring to List.list.op # etc. have to be adapted;
  4322 
  4323 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4324 disabled by default; run isabelle with option -m HOL to get back to
  4325 the original Gordon/HOL-style output;
  4326 
  4327 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4328 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4329 
  4330 * HOL basic syntax simplified (more orthogonal): all variants of
  4331 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4332 Eps operator is provided as well: "SOME x. P[x]";
  4333 
  4334 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4335 
  4336 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4337 thus available for user theories;
  4338 
  4339 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4340 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4341 time;
  4342 
  4343 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4344 several times and then mp;
  4345 
  4346 
  4347 *** LK ***
  4348 
  4349 * the notation <<...>> is now available as a notation for sequences of
  4350 formulas;
  4351 
  4352 * the simplifier is now installed
  4353 
  4354 * the axiom system has been generalized (thanks to Soren Heilmann)
  4355 
  4356 * the classical reasoner now has a default rule database
  4357 
  4358 
  4359 *** ZF ***
  4360 
  4361 * new primrec section allows primitive recursive functions to be given
  4362 directly (as in HOL) over datatypes and the natural numbers;
  4363 
  4364 * new tactics induct_tac and exhaust_tac for induction (or case
  4365 analysis) over datatypes and the natural numbers;
  4366 
  4367 * the datatype declaration of type T now defines the recursor T_rec;
  4368 
  4369 * simplification automatically does freeness reasoning for datatype
  4370 constructors;
  4371 
  4372 * automatic type-inference, with AddTCs command to insert new
  4373 type-checking rules;
  4374 
  4375 * datatype introduction rules are now added as Safe Introduction rules
  4376 to the claset;
  4377 
  4378 * the syntax "if P then x else y" is now available in addition to
  4379 if(P,x,y);
  4380 
  4381 
  4382 *** Internal programming interfaces ***
  4383 
  4384 * tuned simplifier trace output; new flag debug_simp;
  4385 
  4386 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4387 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4388 
  4389 * AxClass.axclass_tac lost the theory argument;
  4390 
  4391 * tuned current_goals_markers semantics: begin / end goal avoids
  4392 printing empty lines;
  4393 
  4394 * removed prs and prs_fn hook, which was broken because it did not
  4395 include \n in its semantics, forcing writeln to add one
  4396 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4397 string -> unit if you really want to output text without newline;
  4398 
  4399 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4400 plain output, interface builders may have to enable 'isabelle_font'
  4401 mode to get Isabelle font glyphs as before;
  4402 
  4403 * refined token_translation interface; INCOMPATIBILITY: output length
  4404 now of type real instead of int;
  4405 
  4406 * theory loader actions may be traced via new ThyInfo.add_hook
  4407 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4408 your own database of information attached to *whole* theories -- as
  4409 opposed to intra-theory data slots offered via TheoryDataFun;
  4410 
  4411 * proper handling of dangling sort hypotheses (at last!);
  4412 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4413 extra sort hypotheses that can be witnessed from the type signature;
  4414 the force_strip_shyps flag is gone, any remaining shyps are simply
  4415 left in the theorem (with a warning issued by strip_shyps_warning);
  4416 
  4417 
  4418 
  4419 New in Isabelle98-1 (October 1998)
  4420 ----------------------------------
  4421 
  4422 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4423 
  4424 * several changes of automated proof tools;
  4425 
  4426 * HOL: major changes to the inductive and datatype packages, including
  4427 some minor incompatibilities of theory syntax;
  4428 
  4429 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4430 called `inj_on';
  4431 
  4432 * HOL: removed duplicate thms in Arith:
  4433   less_imp_add_less  should be replaced by  trans_less_add1
  4434   le_imp_add_le      should be replaced by  trans_le_add1
  4435 
  4436 * HOL: unary minus is now overloaded (new type constraints may be
  4437 required);
  4438 
  4439 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4440 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4441 now taken as an integer constant.
  4442 
  4443 * Pure: ML function 'theory_of' renamed to 'theory';
  4444 
  4445 
  4446 *** Proof tools ***
  4447 
  4448 * Simplifier:
  4449   1. Asm_full_simp_tac is now more aggressive.
  4450      1. It will sometimes reorient premises if that increases their power to
  4451         simplify.
  4452      2. It does no longer proceed strictly from left to right but may also
  4453         rotate premises to achieve further simplification.
  4454      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4455      old Asm_full_simp_tac in that it does not rotate premises.
  4456   2. The simplifier now knows a little bit about nat-arithmetic.
  4457 
  4458 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4459 allows for selected deletion of wrappers, by introduction of names for
  4460 wrapper functionals.  This implies that addbefore, addSbefore,
  4461 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4462 and that adding two tactics with the same name overwrites the first
  4463 one (emitting a warning).
  4464   type wrapper = (int -> tactic) -> (int -> tactic)
  4465   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4466   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4467   delWrapper, delSWrapper: claset *  string            -> claset
  4468   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4469 
  4470 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4471 semantics; addbefore now affects only the unsafe part of step_tac
  4472 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4473 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4474 by Force_tac;
  4475 
  4476 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4477 compWrapper; added safe wrapper (and access functions for it);
  4478 
  4479 * HOL/split_all_tac is now much faster and fails if there is nothing
  4480 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4481 and the names of the automatically generated variables have changed.
  4482 split_all_tac has moved within claset() from unsafe wrappers to safe
  4483 wrappers, which means that !!-bound variables are split much more
  4484 aggressively, and safe_tac and clarify_tac now split such variables.
  4485 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4486 Note: the same holds for record_split_tac, which does the job of
  4487 split_all_tac for record fields.
  4488 
  4489 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4490 permanently to the default simpset using Addsplits just like
  4491 Addsimps. They can be removed via Delsplits just like
  4492 Delsimps. Lower-case versions are also available.
  4493 
  4494 * HOL/Simplifier: The rule split_if is now part of the default
  4495 simpset. This means that the simplifier will eliminate all occurrences
  4496 of if-then-else in the conclusion of a goal. To prevent this, you can
  4497 either remove split_if completely from the default simpset by
  4498 `Delsplits [split_if]' or remove it in a specific call of the
  4499 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4500 other case splitting rules to/from the default simpset: every datatype
  4501 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4502 t is the name of the datatype).
  4503 
  4504 * Classical reasoner / Simplifier combination: new force_tac (and
  4505 derivatives Force_tac, force) combines rewriting and classical
  4506 reasoning (and whatever other tools) similarly to auto_tac, but is
  4507 aimed to solve the given subgoal completely.
  4508 
  4509 
  4510 *** General ***
  4511 
  4512 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4513 and `goalw': the theory is no longer needed as an explicit argument -
  4514 the current theory context is used; assumptions are no longer returned
  4515 at the ML-level unless one of them starts with ==> or !!; it is
  4516 recommended to convert to these new commands using isatool fixgoal
  4517 (backup your sources first!);
  4518 
  4519 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4520 the current theory context, and 'theory' to lookup stored theories;
  4521 
  4522 * new theory section 'locale' for declaring constants, assumptions and
  4523 definitions that have local scope;
  4524 
  4525 * new theory section 'nonterminals' for purely syntactic types;
  4526 
  4527 * new theory section 'setup' for generic ML setup functions
  4528 (e.g. package initialization);
  4529 
  4530 * the distribution now includes Isabelle icons: see
  4531 lib/logo/isabelle-{small,tiny}.xpm;
  4532 
  4533 * isatool install - install binaries with absolute references to
  4534 ISABELLE_HOME/bin;
  4535 
  4536 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4537 
  4538 * print mode 'emacs' reserved for Isamode;
  4539 
  4540 * support multiple print (ast) translations per constant name;
  4541 
  4542 * theorems involving oracles are now printed with a suffixed [!];
  4543 
  4544 
  4545 *** HOL ***
  4546 
  4547 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4548 
  4549 * HOL/inductive package reorganized and improved: now supports mutual
  4550 definitions such as
  4551 
  4552   inductive EVEN ODD
  4553     intrs
  4554       null "0 : EVEN"
  4555       oddI "n : EVEN ==> Suc n : ODD"
  4556       evenI "n : ODD ==> Suc n : EVEN"
  4557 
  4558 new theorem list "elims" contains an elimination rule for each of the
  4559 recursive sets; inductive definitions now handle disjunctive premises
  4560 correctly (also ZF);
  4561 
  4562 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4563 "mutual_induct" no longer exists - the induction rule is always
  4564 contained in "induct";
  4565 
  4566 
  4567 * HOL/datatype package re-implemented and greatly improved: now
  4568 supports mutually recursive datatypes such as
  4569 
  4570   datatype
  4571     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4572             | SUM ('a aexp) ('a aexp)
  4573             | DIFF ('a aexp) ('a aexp)
  4574             | NUM 'a
  4575   and
  4576     'a bexp = LESS ('a aexp) ('a aexp)
  4577             | AND ('a bexp) ('a bexp)
  4578             | OR ('a bexp) ('a bexp)
  4579 
  4580 as well as indirectly recursive datatypes such as
  4581 
  4582   datatype
  4583     ('a, 'b) term = Var 'a
  4584                   | App 'b ((('a, 'b) term) list)
  4585 
  4586 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4587 induction on mutually / indirectly recursive datatypes.
  4588 
  4589 Primrec equations are now stored in theory and can be accessed via
  4590 <function_name>.simps.
  4591 
  4592 INCOMPATIBILITIES:
  4593 
  4594   - Theories using datatypes must now have theory Datatype as an
  4595     ancestor.
  4596   - The specific <typename>.induct_tac no longer exists - use the
  4597     generic induct_tac instead.
  4598   - natE has been renamed to nat.exhaust - use exhaust_tac
  4599     instead of res_inst_tac ... natE. Note that the variable
  4600     names in nat.exhaust differ from the names in natE, this
  4601     may cause some "fragile" proofs to fail.
  4602   - The theorems split_<typename>_case and split_<typename>_case_asm
  4603     have been renamed to <typename>.split and <typename>.split_asm.
  4604   - Since default sorts of type variables are now handled correctly,
  4605     some datatype definitions may have to be annotated with explicit
  4606     sort constraints.
  4607   - Primrec definitions no longer require function name and type
  4608     of recursive argument.
  4609 
  4610 Consider using isatool fixdatatype to adapt your theories and proof
  4611 scripts to the new package (backup your sources first!).
  4612 
  4613 
  4614 * HOL/record package: considerably improved implementation; now
  4615 includes concrete syntax for record types, terms, updates; theorems
  4616 for surjective pairing and splitting !!-bound record variables; proof
  4617 support is as follows:
  4618 
  4619   1) standard conversions (selectors or updates applied to record
  4620 constructor terms) are part of the standard simpset;
  4621 
  4622   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4623 made part of standard simpset and claset via addIffs;
  4624 
  4625   3) a tactic for record field splitting (record_split_tac) is part of
  4626 the standard claset (addSWrapper);
  4627 
  4628 To get a better idea about these rules you may retrieve them via
  4629 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4630 the name of your record type.
  4631 
  4632 The split tactic 3) conceptually simplifies by the following rule:
  4633 
  4634   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4635 
  4636 Thus any record variable that is bound by meta-all will automatically
  4637 blow up into some record constructor term, consequently the
  4638 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4639 solve record problems automatically.
  4640 
  4641 
  4642 * reorganized the main HOL image: HOL/Integ and String loaded by
  4643 default; theory Main includes everything;
  4644 
  4645 * automatic simplification of integer sums and comparisons, using cancellation;
  4646 
  4647 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4648 
  4649 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4650 
  4651 * many new identities for unions, intersections, set difference, etc.;
  4652 
  4653 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4654 called split_if, split_split, split_sum_case and split_nat_case (to go
  4655 with add/delsplits);
  4656 
  4657 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4658 (?x::unit) = (); this is made part of the default simpset, which COULD
  4659 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4660 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4661 unit_abs_eta_conv is added in order to counter the effect of
  4662 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4663 %u.f();
  4664 
  4665 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4666 makes more sense);
  4667 
  4668 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4669   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4670   disjointness reasoning but breaking a few old proofs.
  4671 
  4672 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4673 to 'converse' from 'inverse' (for compatibility with ZF and some
  4674 literature);
  4675 
  4676 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4677 the well-founded relation;
  4678 
  4679 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4680     Compl A.  The "Compl" syntax remains available as input syntax for this
  4681     release ONLY.
  4682 
  4683 * HOL/Update: new theory of function updates:
  4684     f(a:=b) == %x. if x=a then b else f x
  4685 may also be iterated as in f(a:=b,c:=d,...);
  4686 
  4687 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4688 
  4689 * HOL/List:
  4690   - new function list_update written xs[i:=v] that updates the i-th
  4691     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4692   - new function `upt' written [i..j(] which generates the list
  4693     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4694     bound write [i..j], which is a shorthand for [i..j+1(].
  4695   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4696 
  4697 * HOL/Arith:
  4698   - removed 'pred' (predecessor) function;
  4699   - generalized some theorems about n-1;
  4700   - many new laws about "div" and "mod";
  4701   - new laws about greatest common divisors (see theory ex/Primes);
  4702 
  4703 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4704 instead of "inverse";
  4705 
  4706 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4707   of the multiset ordering;
  4708 
  4709 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4710   (not included by default);
  4711 
  4712 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4713 
  4714 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4715   programs, i.e. different program variables may have different types.
  4716 
  4717 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4718   [previously, this check worked only if the rewrite rule was unconditional]
  4719   Now rew can involve either definitions or equalities (either == or =).
  4720 
  4721 
  4722 *** ZF ***
  4723 
  4724 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4725   only the theorems proved on ZF.ML;
  4726 
  4727 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4728   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4729   disjointness reasoning but breaking a few old proofs.
  4730 
  4731 * ZF/Update: new theory of function updates
  4732     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4733   may also be iterated as in f(a:=b,c:=d,...);
  4734 
  4735 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4736 
  4737 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4738   [previously, this check worked only if the rewrite rule was unconditional]
  4739   Now rew can involve either definitions or equalities (either == or =).
  4740 
  4741 * case_tac provided for compatibility with HOL
  4742     (like the old excluded_middle_tac, but with subgoals swapped)
  4743 
  4744 
  4745 *** Internal programming interfaces ***
  4746 
  4747 * Pure: several new basic modules made available for general use, see
  4748 also src/Pure/README;
  4749 
  4750 * improved the theory data mechanism to support encapsulation (data
  4751 kind name replaced by private Object.kind, acting as authorization
  4752 key); new type-safe user interface via functor TheoryDataFun; generic
  4753 print_data function becomes basically useless;
  4754 
  4755 * removed global_names compatibility flag -- all theory declarations
  4756 are qualified by default;
  4757 
  4758 * module Pure/Syntax now offers quote / antiquote translation
  4759 functions (useful for Hoare logic etc. with implicit dependencies);
  4760 see HOL/ex/Antiquote for an example use;
  4761 
  4762 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4763 cterm -> thm;
  4764 
  4765 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4766 subgoal;
  4767 
  4768 * Display.print_goals function moved to Locale.print_goals;
  4769 
  4770 * standard print function for goals supports current_goals_markers
  4771 variable for marking begin of proof, end of proof, start of goal; the
  4772 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4773 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4774 for example;
  4775 
  4776 
  4777 
  4778 New in Isabelle98 (January 1998)
  4779 --------------------------------
  4780 
  4781 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4782 
  4783 * changed lexical syntax of terms / types: dots made part of long
  4784 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4785 
  4786 * simpset (and claset) reference variable replaced by functions
  4787 simpset / simpset_ref;
  4788 
  4789 * no longer supports theory aliases (via merge) and non-trivial
  4790 implicit merge of thms' signatures;
  4791 
  4792 * most internal names of constants changed due to qualified names;
  4793 
  4794 * changed Pure/Sequence interface (see Pure/seq.ML);
  4795 
  4796 
  4797 *** General Changes ***
  4798 
  4799 * hierachically structured name spaces (for consts, types, axms, thms
  4800 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4801 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4802 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4803 long_names for fully qualified output names; NOTE: ML programs
  4804 (special tactics, packages etc.) referring to internal names may have
  4805 to be adapted to cope with fully qualified names; in case of severe
  4806 backward campatibility problems try setting 'global_names' at compile
  4807 time to have enrything declared within a flat name space; one may also
  4808 fine tune name declarations in theories via the 'global' and 'local'
  4809 section;
  4810 
  4811 * reimplemented the implicit simpset and claset using the new anytype
  4812 data filed in signatures; references simpset:simpset ref etc. are
  4813 replaced by functions simpset:unit->simpset and
  4814 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4815 to patch your ML files accordingly;
  4816 
  4817 * HTML output now includes theory graph data for display with Java
  4818 applet or isatool browser; data generated automatically via isatool
  4819 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4820 
  4821 * defs may now be conditional; improved rewrite_goals_tac to handle
  4822 conditional equations;
  4823 
  4824 * defs now admits additional type arguments, using TYPE('a) syntax;
  4825 
  4826 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4827 creates a new theory node; implicit merge of thms' signatures is
  4828 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4829 transfer:theory->thm->thm in (rare) cases;
  4830 
  4831 * improved handling of draft signatures / theories; draft thms (and
  4832 ctyps, cterms) are automatically promoted to real ones;
  4833 
  4834 * slightly changed interfaces for oracles: admit many per theory, named
  4835 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4836 
  4837 * print_goals: optional output of const types (set show_consts and
  4838 show_types);
  4839 
  4840 * improved output of warnings (###) and errors (***);
  4841 
  4842 * subgoal_tac displays a warning if the new subgoal has type variables;
  4843 
  4844 * removed old README and Makefiles;
  4845 
  4846 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4847 
  4848 * removed obsolete init_pps and init_database;
  4849 
  4850 * deleted the obsolete tactical STATE, which was declared by
  4851     fun STATE tacfun st = tacfun st st;
  4852 
  4853 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4854 (which abbreviates $HOME);
  4855 
  4856 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4857 use isatool fixseq to adapt your ML programs (this works for fully
  4858 qualified references to the Sequence structure only!);
  4859 
  4860 * use_thy no longer requires writable current directory; it always
  4861 reloads .ML *and* .thy file, if either one is out of date;
  4862 
  4863 
  4864 *** Classical Reasoner ***
  4865 
  4866 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4867 tactics that use classical reasoning to simplify a subgoal without
  4868 splitting it into several subgoals;
  4869 
  4870 * Safe_tac: like safe_tac but uses the default claset;
  4871 
  4872 
  4873 *** Simplifier ***
  4874 
  4875 * added simplification meta rules:
  4876     (asm_)(full_)simplify: simpset -> thm -> thm;
  4877 
  4878 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4879 logics (again);
  4880 
  4881 * added prems argument to simplification procedures;
  4882 
  4883 * HOL, FOL, ZF: added infix function `addsplits':
  4884   instead of `<simpset> setloop (split_tac <thms>)'
  4885   you can simply write `<simpset> addsplits <thms>'
  4886 
  4887 
  4888 *** Syntax ***
  4889 
  4890 * TYPE('a) syntax for type reflection terms;
  4891 
  4892 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4893 
  4894 * pretty printer: changed order of mixfix annotation preference (again!);
  4895 
  4896 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4897 
  4898 
  4899 *** HOL ***
  4900 
  4901 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4902   with `addloop' of the simplifier to faciliate case splitting in premises.
  4903 
  4904 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4905 
  4906 * HOL/Auth: new protocol proofs including some for the Internet
  4907   protocol TLS;
  4908 
  4909 * HOL/Map: new theory of `maps' a la VDM;
  4910 
  4911 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4912 cancelling out common nat summands from =, <, <= (in)equalities, or
  4913 differences; simplification procedures nat_cancel_factor for
  4914 cancelling common factor from =, <, <= (in)equalities over natural
  4915 sums; nat_cancel contains both kinds of procedures, it is installed by
  4916 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4917 
  4918 * HOL/simplifier: terms of the form
  4919   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4920   are rewritten to
  4921   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4922   and those of the form
  4923   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4924   are rewritten to
  4925   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4926 
  4927 * HOL/datatype
  4928   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4929 
  4930   P(t_case f1 ... fn x) =
  4931      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4932         ...
  4933        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4934      )
  4935 
  4936   and a theorem `split_t_case_asm' of the form
  4937 
  4938   P(t_case f1 ... fn x) =
  4939     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4940         ...
  4941        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4942      )
  4943   which can be added to a simpset via `addsplits'. The existing theorems
  4944   expand_list_case and expand_option_case have been renamed to
  4945   split_list_case and split_option_case.
  4946 
  4947 * HOL/Arithmetic:
  4948   - `pred n' is automatically converted to `n-1'.
  4949     Users are strongly encouraged not to use `pred' any longer,
  4950     because it will disappear altogether at some point.
  4951   - Users are strongly encouraged to write "0 < n" rather than
  4952     "n ~= 0". Theorems and proof tools have been modified towards this
  4953     `standard'.
  4954 
  4955 * HOL/Lists:
  4956   the function "set_of_list" has been renamed "set" (and its theorems too);
  4957   the function "nth" now takes its arguments in the reverse order and
  4958   has acquired the infix notation "!" as in "xs!n".
  4959 
  4960 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4961 
  4962 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4963   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4964 
  4965 * HOL/record: extensible records with schematic structural subtyping
  4966 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4967 still lacks various theorems and concrete record syntax;
  4968 
  4969 
  4970 *** HOLCF ***
  4971 
  4972 * removed "axioms" and "generated by" sections;
  4973 
  4974 * replaced "ops" section by extended "consts" section, which is capable of
  4975   handling the continuous function space "->" directly;
  4976 
  4977 * domain package:
  4978   . proves theorems immediately and stores them in the theory,
  4979   . creates hierachical name space,
  4980   . now uses normal mixfix annotations (instead of cinfix...),
  4981   . minor changes to some names and values (for consistency),
  4982   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4983   . separator between mutual domain defs: changed "," to "and",
  4984   . improved handling of sort constraints;  now they have to
  4985     appear on the left-hand side of the equations only;
  4986 
  4987 * fixed LAM <x,y,zs>.b syntax;
  4988 
  4989 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4990 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4991 
  4992 
  4993 *** FOL and ZF ***
  4994 
  4995 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4996   with `addloop' of the simplifier to faciliate case splitting in premises.
  4997 
  4998 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4999 in HOL, they strip ALL and --> from proved theorems;
  5000 
  5001 
  5002 
  5003 New in Isabelle94-8 (May 1997)
  5004 ------------------------------
  5005 
  5006 *** General Changes ***
  5007 
  5008 * new utilities to build / run / maintain Isabelle etc. (in parts
  5009 still somewhat experimental); old Makefiles etc. still functional;
  5010 
  5011 * new 'Isabelle System Manual';
  5012 
  5013 * INSTALL text, together with ./configure and ./build scripts;
  5014 
  5015 * reimplemented type inference for greater efficiency, better error
  5016 messages and clean internal interface;
  5017 
  5018 * prlim command for dealing with lots of subgoals (an easier way of
  5019 setting goals_limit);
  5020 
  5021 
  5022 *** Syntax ***
  5023 
  5024 * supports alternative (named) syntax tables (parser and pretty
  5025 printer); internal interface is provided by add_modesyntax(_i);
  5026 
  5027 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5028 be used in conjunction with the Isabelle symbol font; uses the
  5029 "symbols" syntax table;
  5030 
  5031 * added token_translation interface (may translate name tokens in
  5032 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5033 the current print_mode); IMPORTANT: user print translation functions
  5034 are responsible for marking newly introduced bounds
  5035 (Syntax.mark_boundT);
  5036 
  5037 * token translations for modes "xterm" and "xterm_color" that display
  5038 names in bold, underline etc. or colors (which requires a color
  5039 version of xterm);
  5040 
  5041 * infixes may now be declared with names independent of their syntax;
  5042 
  5043 * added typed_print_translation (like print_translation, but may
  5044 access type of constant);
  5045 
  5046 
  5047 *** Classical Reasoner ***
  5048 
  5049 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5050 some limitations.  Blast_tac...
  5051   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5052   + ignores elimination rules that don't have the correct format
  5053         (the conclusion MUST be a formula variable)
  5054   + ignores types, which can make HOL proofs fail
  5055   + rules must not require higher-order unification, e.g. apply_type in ZF
  5056     [message "Function Var's argument not a bound variable" relates to this]
  5057   + its proof strategy is more general but can actually be slower
  5058 
  5059 * substitution with equality assumptions no longer permutes other
  5060 assumptions;
  5061 
  5062 * minor changes in semantics of addafter (now called addaltern); renamed
  5063 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5064 (and access functions for it);
  5065 
  5066 * improved combination of classical reasoner and simplifier:
  5067   + functions for handling clasimpsets
  5068   + improvement of addss: now the simplifier is called _after_ the
  5069     safe steps.
  5070   + safe variant of addss called addSss: uses safe simplifications
  5071     _during_ the safe steps. It is more complete as it allows multiple
  5072     instantiations of unknowns (e.g. with slow_tac).
  5073 
  5074 *** Simplifier ***
  5075 
  5076 * added interface for simplification procedures (functions that
  5077 produce *proven* rewrite rules on the fly, depending on current
  5078 redex);
  5079 
  5080 * ordering on terms as parameter (used for ordered rewriting);
  5081 
  5082 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5083 
  5084 * the solver is now split into a safe and an unsafe part.
  5085 This should be invisible for the normal user, except that the
  5086 functions setsolver and addsolver have been renamed to setSolver and
  5087 addSolver; added safe_asm_full_simp_tac;
  5088 
  5089 
  5090 *** HOL ***
  5091 
  5092 * a generic induction tactic `induct_tac' which works for all datatypes and
  5093 also for type `nat';
  5094 
  5095 * a generic case distinction tactic `exhaust_tac' which works for all
  5096 datatypes and also for type `nat';
  5097 
  5098 * each datatype comes with a function `size';
  5099 
  5100 * patterns in case expressions allow tuple patterns as arguments to
  5101 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5102 
  5103 * primrec now also works with type nat;
  5104 
  5105 * recdef: a new declaration form, allows general recursive functions to be
  5106 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5107 
  5108 * the constant for negation has been renamed from "not" to "Not" to
  5109 harmonize with FOL, ZF, LK, etc.;
  5110 
  5111 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5112 infinite lists;
  5113 
  5114 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5115 
  5116 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5117 problems in commutative rings, using axiomatic type classes for + and *;
  5118 
  5119 * more examples in HOL/MiniML and HOL/Auth;
  5120 
  5121 * more default rewrite rules for quantifiers, union/intersection;
  5122 
  5123 * a new constant `arbitrary == @x.False';
  5124 
  5125 * HOLCF/IOA replaces old HOL/IOA;
  5126 
  5127 * HOLCF changes: derived all rules and arities
  5128   + axiomatic type classes instead of classes
  5129   + typedef instead of faking type definitions
  5130   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5131   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5132   + eliminated the types void, one, tr
  5133   + use unit lift and bool lift (with translations) instead of one and tr
  5134   + eliminated blift from Lift3.thy (use Def instead of blift)
  5135   all eliminated rules are derived as theorems --> no visible changes ;
  5136 
  5137 
  5138 *** ZF ***
  5139 
  5140 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5141 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5142 as ZF_cs addSIs [equalityI];
  5143 
  5144 
  5145 
  5146 New in Isabelle94-7 (November 96)
  5147 ---------------------------------
  5148 
  5149 * allowing negative levels (as offsets) in prlev and choplev;
  5150 
  5151 * super-linear speedup for large simplifications;
  5152 
  5153 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5154 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5155 FAIL); can suppress it using the command Delsimps (ex_simps @
  5156 all_simps); De Morgan laws are also now included, by default;
  5157 
  5158 * improved printing of ==>  :  ~:
  5159 
  5160 * new object-logic "Sequents" adds linear logic, while replacing LK
  5161 and Modal (thanks to Sara Kalvala);
  5162 
  5163 * HOL/Auth: correctness proofs for authentication protocols;
  5164 
  5165 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5166 examples on HOL/Auth);
  5167 
  5168 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5169 the rewriter and classical reasoner simultaneously;
  5170 
  5171 * function uresult no longer returns theorems in "standard" format;
  5172 regain previous version by: val uresult = standard o uresult;
  5173 
  5174 
  5175 
  5176 New in Isabelle94-6
  5177 -------------------
  5178 
  5179 * oracles -- these establish an interface between Isabelle and trusted
  5180 external reasoners, which may deliver results as theorems;
  5181 
  5182 * proof objects (in particular record all uses of oracles);
  5183 
  5184 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5185 
  5186 * "constdefs" section in theory files;
  5187 
  5188 * "primrec" section (HOL) no longer requires names;
  5189 
  5190 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5191 
  5192 
  5193 
  5194 New in Isabelle94-5
  5195 -------------------
  5196 
  5197 * reduced space requirements;
  5198 
  5199 * automatic HTML generation from theories;
  5200 
  5201 * theory files no longer require "..." (quotes) around most types;
  5202 
  5203 * new examples, including two proofs of the Church-Rosser theorem;
  5204 
  5205 * non-curried (1994) version of HOL is no longer distributed;
  5206 
  5207 
  5208 
  5209 New in Isabelle94-4
  5210 -------------------
  5211 
  5212 * greatly reduced space requirements;
  5213 
  5214 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5215 
  5216 * searchable theorem database (see the section "Retrieving theorems" on
  5217 page 8 of the Reference Manual);
  5218 
  5219 * new examples, including Grabczewski's monumental case study of the
  5220 Axiom of Choice;
  5221 
  5222 * The previous version of HOL renamed to Old_HOL;
  5223 
  5224 * The new version of HOL (previously called CHOL) uses a curried syntax
  5225 for functions.  Application looks like f a b instead of f(a,b);
  5226 
  5227 * Mutually recursive inductive definitions finally work in HOL;
  5228 
  5229 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5230 translates to the operator "split";
  5231 
  5232 
  5233 
  5234 New in Isabelle94-3
  5235 -------------------
  5236 
  5237 * new infix operator, addss, allowing the classical reasoner to
  5238 perform simplification at each step of its search.  Example:
  5239         fast_tac (cs addss ss)
  5240 
  5241 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5242 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5243 look like (a,b) instead of <a,b>;
  5244 
  5245 * PLEASE NOTE: CHOL will eventually replace HOL!
  5246 
  5247 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5248 It translates to the operator "split".  A new theory of integers is available;
  5249 
  5250 * In ZF, integer numerals now denote two's-complement binary integers.
  5251 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5252 
  5253 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5254 of the Axiom of Choice;
  5255 
  5256 
  5257 
  5258 New in Isabelle94-2
  5259 -------------------
  5260 
  5261 * Significantly faster resolution;
  5262 
  5263 * the different sections in a .thy file can now be mixed and repeated
  5264 freely;
  5265 
  5266 * Database of theorems for FOL, HOL and ZF.  New
  5267 commands including qed, qed_goal and bind_thm store theorems in the database.
  5268 
  5269 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5270 a given theory (thms_of), or find out what theory a theorem was proved in
  5271 (theory_of_thm);
  5272 
  5273 * Bugs fixed in the inductive definition and datatype packages;
  5274 
  5275 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5276 and HOL_dup_cs obsolete;
  5277 
  5278 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5279 have been removed;
  5280 
  5281 * Simpler definition of function space in ZF;
  5282 
  5283 * new results about cardinal and ordinal arithmetic in ZF;
  5284 
  5285 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5286 types;
  5287 
  5288 :mode=text:wrap=hard:maxLineLen=72:
  5289 
  5290 $Id$